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in assigning r s configuration which among the following groups has highest priority

  • General Organic Chemistry

in assigning r s configuration which among the following groups has highest priority

In assigning R-S configuration which among the following groups has highest priority? A. $ - {\text{S}}{{\text{O}}_3}{\text{H}}$ B. $ - {\text{COOH}}$ C. $ - {\text{CHO}}$ D. $ - {{\text{C}}_6}{{\text{H}}_5}$

in assigning r s configuration which among the following groups has highest priority

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Q. In assigning R − S configuration which among the following groups has highest priority ?

− s o 3 ​ h, − c 6 ​ h 5 ​, in r-s configuration, priority sequence is decided by the atoms directly attached to the chiral carbon arranged in decreasing atomic number. from the given groups, sulphur (s) has the highest atomic number i.e., 16 therefore, it gets highest priority., questions from organic chemistry – some basic principles and techniques, 1. only s p and s p 2 hybrid orbitals are involved in the formation of, 2. c 2 ​ h 2 ​ molecule is, 3. in hexa- 1 , 3 -diene- 5 -yne the number of c − c σ , c − c π and c − h σ bonds respectively are, 4. the general molecular formula for a cycloalkyl group is, 5. iupac name of, questions from mht cet 2017, 1. aldehydes or ketones when treated with c 6 ​ h 5 ​ − n h − n h 2 ​ , the product formed is, 2. solubility of which among the following solids in water changes slightly with temperature , 3. what is the quantity of hydrogen gas liberated when 46 g sodium reacts with excess ethanol (given at. mass of na = 23), 4. identify the weakest oxidising agent among the following., 5. the monomers used in preparation of dextron are, 6. which among the following compounds does not act as a reducing agent , 7. which of the following processes is not used to preserve the food , 8. in case of substituted aniline the group which decreases the basic strength is, 9. which among the following equations represents arrhenius equation , 10. which of the following compounds will give positive iodoform test .

in assigning r s configuration which among the following groups has highest priority

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Which among the following functional groups has been given the highest priority while assigning R-S configuration

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R and S configuration same atoms

Organic Chemistry

Stereochemistry, what is the r and s configuration and why do we need it.

If we name these two alkyl halides based on the IUPAC nomenclature rules, we get the name as 2-chlorobutanbe for both:

in assigning r s configuration which among the following groups has highest priority

However, they don’t look exactly the same as the Cl atom points in different directions – wedge and dash. These molecules are not the same compound – they are non-superimposable mirror images which are known as enantiomers :

in assigning r s configuration which among the following groups has highest priority

The problem with the wedge and dash notation is that it is not a universal approach and quickly loses validity when we simply look at the molecule from the opposite direction:

in assigning r s configuration which among the following groups has highest priority

So, we need an extra piece of information to distinguish enantiomers (and other stereoisomers) by their names properly addressing the stereochemistry as well.

Cahn, Ingold, and Prelog developed a system that, regardless of the direction we are looking at the molecule, will always give the same name ( unlike the wedge and dash notation ).

And that is why this is also known as the absolute Configuration or most commonly referred to as the R and S system.

Let’s see how it works by looking first at the following molecule and we will get back to the 2-chlorobutane after that:

in assigning r s configuration which among the following groups has highest priority

Assigning R and S Configuration: Steps and Rules

To assign the absolute configuration, we need to first locate the carbon(s) with four different groups (atoms) connected to it. These are called chirality centers (chiral center, stereogenic center).

In our molecule, we only have one carbon with four different groups and that is the one with the bromine and we are going to assign the absolute configuration of this chiral center.

in assigning r s configuration which among the following groups has highest priority

For this, you need to follow the steps and rules of the Cahn-Ingold-Prelog system.

Give each atom connected to the chiral center a priority based on its atomic number . The higher the atomic number, the higher the priority.

So, based on this, bromine gets priority one, the oxygen gets priority two, the methyl carbon is the third and the hydrogen is the lowest priority-four:

in assigning r s configuration which among the following groups has highest priority

Draw an arrow starting from priority one and going to priority two and then to priority 3:

in assigning r s configuration which among the following groups has highest priority

If the arrow goes clockwise , like in this case, the absolute configuration is R .

As opposed to this, if the arrow goes counterclockwise then the absolute configuration is S .

As an example, in the following molecule, the priorities go Cl > N > C > H and the counterclockwise direction of the arrow indicates an S absolute configuration:

in assigning r s configuration which among the following groups has highest priority

So, remember: Clockwise – R , Counterclockwise – S .

Now, let’s see what would be the absolute configuration of the enantiomer:

in assigning r s configuration which among the following groups has highest priority

The priorities are still the same since all the groups around the carbon are the same. Starting from the bromine and going to the oxygen and then the carbon, we can see that this time the arrow goes counterclockwise. If the arrow goes counterclockwise , the absolute configuration is S .

in assigning r s configuration which among the following groups has highest priority

And this is another important thing to remember:

All the chirality centers in enantiomers are inverted (every R is S , every S is R in the enantiomer).

So, we discussed the roles of priorities 1, 2, and 3 but what about the lowest priority? We did not mention anything about the arrow going to it. Is it part of the game and how do you use it?

The lowest priority does not affect the direction of the arrow. However, this is very important, and it is a requirement when assigning the R and S configuration, that;

The lowest priority must point away from the viewer .

In other words, the lowest priority must be a dashed line to assign the R and S based on the direction of the arrow as we just did:

in assigning r s configuration which among the following groups has highest priority

With that in mind, how can we assign the absolute configuration of this molecule where the hydrogen is a wedge line pointing towards us?

R and S When the lowest priority is a wedge

in assigning r s configuration which among the following groups has highest priority

You have two options here:

Option one. Turn the molecule 180 o such that the hydroxyl is now pointing towards you and the hydrogen is pointing away. This allows to have the molecule drawn as needed – the lowest priority pointing backward as it is supposed to be for determining the R and S configuration:

in assigning r s configuration which among the following groups has highest priority

Next, assign the priorities; chlorine-number one, oxygen-two, carbon-three and the H as number four.

in assigning r s configuration which among the following groups has highest priority

The arrow goes clockwise , therefore the absolute configuration is R .

The problem with this approach is that sometimes you will work with larger molecules and it is impractical to redraw the entire molecule and swap every single chirality center.

For example, look at biotin with all these hydrogens pointing forward. Not the best option to redraw this molecule changing all the hydrogens and keeping the rest of the molecule as it should be.

in assigning r s configuration which among the following groups has highest priority

This is why we have the second approach which is what everyone normally follows.

Here, you leave the molecule as it is with the hydrogen pointing towards you . Continue as you would normally do by assigning the priorities and drawing the arrow.

in assigning r s configuration which among the following groups has highest priority

The only thing you have to do at the end is change the result from R to S or from S to R .

In this case, the arrow goes counterclockwise but because the hydrogen is pointing towards us, we change the result from S to R .

Of course, either approach should give the same result as this is the same molecule drawn differently.

in assigning r s configuration which among the following groups has highest priority

R and S When Group #4 is not a Wedge or a Dash

There is a third possibility for the position of group 4 and that is when it is neither pointing away or towards you. This means we cannot determine the configuration as easily as if the lowest priority was pointing towards or away from us, and then switch it at the end as we did when group 4 was a wedge line.

As an example, what would be the configuration of this molecule?

in assigning r s configuration which among the following groups has highest priority

For this, there is this simple yet such a useful trick making life a lot easier. Remember it:

Swapping any two groups on a chiral center inverts its absolute configuration ( R to S , S to R ):

in assigning r s configuration which among the following groups has highest priority

Notice that these are different molecules. We are not talking about rotating about an axis or a single bond, in which case the absolute configuration(s) must stay the same. We are actually converting to a different molecule by swapping the groups to make it easier determining the R and S configuration.

Let’s do this on the molecule mentioned above:

The lowest priority group is in the drawing plane , so what we can do is swap it with the one that is pointing away from us (Br). After determining the R and S we switch the result since swapping means changing the absolute configuration and we need to switch back again.

in assigning r s configuration which among the following groups has highest priority

The arrow goes counterclockwise indicating S  configuration and this means in the original molecule it is R.

Alternatively, which is more time-consuming, you can draw the Newman projection of the molecule looking from the angle that places group 4 in the back (pointing away from the viewer):

in assigning r s configuration which among the following groups has highest priority

The lowest priority group is pointing and therefore, the clockwise direction of the arrow indicates an R configuration.

These two articles will be very helpful when dealing with stereochemistry in Newman projectiopns:

R and S when Atoms (groups) are the same

Sometimes it happens that two or more atoms connected to the chiral center are the same and it is not possible to assign the priorities right away.

For example, let’s go back to the 2-chlorobutane starting with the wedge chlorine:

in assigning r s configuration which among the following groups has highest priority

Chlorine is the first priority, then we have two carbons and a hydrogen which gets the lowest priority. We need to determine the second priority comparing two carbon atoms and there is a tie since they both (obviously) have the same atomic number.

What do you do? You need to look at the atoms connected to the ones you compare:

in assigning r s configuration which among the following groups has highest priority

The carbon on the left (CH 3 ) is connected to three hydrogens, while the one on the right is connected to two hydrogens and one carbon. This extra carbon gives the second priority to the CH 2 and the CH 3 gets priority three.

The arrow goes clockwise, so this is the ( R )-2-chlorobutane.

And if these atoms were identical as well, we’d have to move farther away from the chiral center and repeat the process until we get to the first point of difference.

It is like layers: the first layer is the atoms connected to the chiral center and you are comparing those and only move to the second layer if there is a tie.

in assigning r s configuration which among the following groups has highest priority

You should never compare any atom of the second layer to a first layer atom regardless of its atomic number. For example, in the following molecule, layer 1 is a tie so we proceed to layer 2 which gives the priority to the carbon connected to the chiral center on the left since it has oxygen connected to it.

in assigning r s configuration which among the following groups has highest priority

So, we do not compare layer 2 and 3 which would’ve given the priority to the carbon with a Br since Br has a higher atomic number than oxygen. Because the oxygen is connected to a carbon closer to the chiral center, it gives the prioirty to that carbon regardless of what is connected to the carbon atoms on the next layer:

in assigning r s configuration which among the following groups has highest priority

Double and triple bonds in the R and S configurations

  Let’s do the R and S for this molecule:

in assigning r s configuration which among the following groups has highest priority

Bromine is the priority and the hydrogen is number four. Carbon “a” is connected to one oxygen and two hydrogens. Carbon “b” is connected to one oxygen and one hydrogen. However, because of the double bond , carbon “b” is treated as if it is connected to two oxygens . The same rule is applied for any other double or triple bond. So, when you see a double bond count it as two single bonds when you see a triple bond cut it as three single bonds .

The arrow goes clockwise, however, the absolute configuration is S , because the hydrogen is pointing towards us.

More Tricks in the R and S configurations

Let’s see this with this molecule:

in assigning r s configuration which among the following groups has highest priority

Even if only one atom has a higher atomic number than the highest one on the other carbon, the group gets higher priority.

So, one S beats N, O, F because it has a higher atomic number than the others individually.

in assigning r s configuration which among the following groups has highest priority

in assigning r s configuration which among the following groups has highest priority

in assigning r s configuration which among the following groups has highest priority

in assigning r s configuration which among the following groups has highest priority

in assigning r s configuration which among the following groups has highest priority

And that should cover most possibilities that I can think of about R and S configurations.

Let me know in the comments if there are any other tips and tricks you would like to be mentioned. 

Practicing R and S is never too much. This 1.5-hour video is a collection of examples taken from the multiple choice quizzes determining the R and S configuration in the context of naming compounds, determining the relationship between compounds, and chemical reactions. 

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Check Also in Stereochemistry:

in assigning r s configuration which among the following groups has highest priority

Stereochemistry Practice Problems Quiz

Identify all the chiral centers in each molecule and determine the absolute configuration as R or S :

in assigning r s configuration which among the following groups has highest priority

Identify all the chiral centers in each Fischer projection  and determine the absolute configuration as R or S :

in assigning r s configuration which among the following groups has highest priority

For each of the following pairs of compounds, determine the relationship between the two compounds: Are they enantiomers or the same compound drawn differently? If you hesitate, determine the absolute configuration of chiral centers (if any:  R or S ).

in assigning r s configuration which among the following groups has highest priority

Determine the absolute configuration of each chiral center in the following Newman projections:

in assigning r s configuration which among the following groups has highest priority

15 thoughts on “How to Determine the R and S configuration”

Thanks for sharing this useful article for finding out the Absolute configuartion

This was such a good article to explain things! A big thanku

Thanks for the kind words

Thanks for sharing this article we got a lot of help thanks❤️❤️❤️

Great to hear that, Ali.

I was wondering how the different layers were given priority, as my teacher did not cover that part but still expected us to know R or S configuration. Thanks for explaining it so well visually!

Glad it was helpful, Aron.

Thank you, it really help and Interesting

R and S do not apply to the nitrogen in amines for the same reason as for carbanions. Quaternary ammonium groups, however, can be chiral ( in the last example ). In this section the lower priority group is in the plane , it should be below the plane . Then will it be a R- configuration? It may be S-configuration , do check please.

Correct, the lower priority is the methyl group and it is in the plane. One option to make it appear in the back is to look at the molecule from the opposite direction of where the methyl is pointing – 10 o’clock. From there, the arrow would look like going clockwise based on the priorities assigned shown in the example, so the absolute configuration is R.

Thanks so much for the in-depth article and thorough treatment of techniques to approach chirality! It seems that our textbook just loves to share the basic principles but fails to help when things get sticky–leaving me to flounder on the trick exam questions! I feel much more confident about my knowledge of chirality after reading through your extremely thoughtful article.

Thank you for your feedback. It does take time to write the articles around the situations where I see students getting stuck in the class, and it is great to see it is helpful.

This is so understandable and straight forward. Thanks for the help, it’s really useful.

Thanks for the good feedback!

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Chemistry LibreTexts

7.2: Naming chiral centers: the R and S system

Chemists need a convenient way to distinguish one stereoisomer from another. The Cahn-Ingold-Prelog system is a set of rules that allows us to unambiguously define the stereochemical configuration of any stereocenter, using the designations ' R ’ (from the Latin rectus , meaning right-handed) or ' S ’ (from the Latin sinister , meaning left-handed).

The rules for this system of stereochemical nomenclature are, on the surface, fairly simple.

Rules for assigning an R/S designation to a chiral center

1: Assign priorities to the four substituents, with #1 being the highest priority and #4 the lowest. Priorities are based on the atomic number.

2: Trace a circle from #1 to #2 to #3.

3: Determine the orientation of the #4 priority group. If it is oriented into the plane of the page (away from you), go to step 4a. If it is oriented out of the plane of the page (toward you) go to step 4b.

4a: (#4 group pointing away from you ): a clockwise circle in part 2 corresponds to the R configuration, while a counterclockwise circle corresponds to the S configuration.

4b: (#4 group pointing toward you ): a clockwise circle in part 2 corresponds to the S configuration, while a counterclockwise circle corresponds to the R configuration.

We’ll use the 3-carbon sugar glyceraldehyde as our first example. The first thing that we must do is to assign a priority to each of the four substituents bound to the chiral center. We first look at the atoms that are directly bonded to the chiral center: these are H, O (in the hydroxyl), C (in the aldehyde), and C (in the CH 2 OH group).

Assigning R/S configuration to glyceraldehyde

Two priorities are easy: hydrogen, with an atomic number of 1, is the lowest (#4) priority, and the hydroxyl oxygen, with atomic number 8, is priority #1. Carbon has an atomic number of 6. Which of the two ‘C’ groups is priority #2, the aldehyde or the CH 2 OH? To determine this, we move one more bond away from the chiral center: for the aldehyde we have a double bond to an oxygen, while on the CH 2 OH group we have a single bond to an oxygen. If the atom is the same, double bonds have a higher priority than single bonds. Therefore, the aldehyde group is assigned #2 priority and the CH 2 OH group the #3 priority.

With our priorities assigned, we look next at the #4 priority group (the hydrogen) and see that it is pointed back away from us, into the plane of the page - thus step 4a from the procedure above applies. Then, we trace a circle defined by the #1, #2, and #3 priority groups, in increasing order. The circle is clockwise, which by step 4a tells us that this carbon has the ‘ R ’ configuration, and that this molecule is ( R )-glyceraldehyde. Its enantiomer, by definition, must be ( S )-glyceraldehyde.

Next, let's look at one of the enantiomers of lactic acid and determine the configuration of the chiral center. Clearly, H is the #4 substituent and OH is #1. Owing to its three bonds to oxygen, the carbon on the acid group takes priority #2, and the methyl group takes #3. The #4 group, hydrogen, happens to be drawn pointing toward us (out of the plane of the page) in this figure, so we use step 4b: The circle traced from #1 to #2 to #3 is clockwise, which means that the chiral center has the S configuration.

Molecule of (s)-lactic acid. O H group has first priority, carboxylic acid has second priority, methyl has third priority and hydrogen has lowest priority. Clockwise but lowest priority group is pointing towards us (wedged) so it is an S enantiomer.

Interactive model of (S)-alanine

The drug thalidomide is an interesting - but tragic - case study in the importance of stereochemistry in drug design. First manufactured by a German drug company and prescribed widely in Europe and Australia in the late 1950's as a sedative and remedy for morning sickness in pregnant women, thalidomide was soon implicated as the cause of devastating birth defects in babies born to women who had taken it. Thalidomide contains a chiral center, and thus exists in two enantiomeric forms. It was marketed as a racemic mixture : in other words, a 50:50 mixture of both enantiomers.

Two enantiomers of thalidomide. Left: nitrogen on wedge. Right: nitrogen on dash.

Let’s try to determine the stereochemical configuration of the enantiomer on the left. Of the four bonds to the chiral center, the #4 priority is hydrogen. The nitrogen group is #1, the carbonyl side of the ring is #2, and the –CH 2 side of the ring is #3.

R-thalidomide molecule with priority groups numbered. Amine group has highest priority, carbon double bonded to oxygen has second priority and C H 2has third priority. Hydrogen has lowest priority and is on a dash. Priority groups go in clockwise direction. R configuration.

The hydrogen is shown pointing away from us, and the prioritized substituents trace a clockwise circle: this is the R enantiomer of thalidomide. The other enantiomer, of course, must have the S configuration.

Although scientists are still unsure today how thalidomide works, experimental evidence suggests that it was actually the R enantiomer that had the desired medical effects, while the S enantiomer caused the birth defects. Even with this knowledge, however, pure ( R )-thalidomide is not safe, because enzymes in the body rapidly convert between the two enantiomers - we will see how that happens in chapter 12.

As a historical note, thalidomide was never approved for use in the United States. This was thanks in large part to the efforts of Dr. Frances Kelsey, a Food and Drug officer who, at peril to her career, blocked its approval due to her concerns about the lack of adequate safety studies, particularly with regard to the drug's ability to enter the bloodstream of a developing fetus. Unfortunately, though, at that time clinical trials for new drugs involved widespread and unregulated distribution to doctors and their patients across the country, so families in the U.S. were not spared from the damage caused.

Very recently a close derivative of thalidomide has become legal to prescribe again in the United States, with strict safety measures enforced, for the treatment of a form of blood cancer called multiple myeloma. In Brazil, thalidomide is used in the treatment of leprosy - but despite safety measures, children are still being born with thalidomide-related defects.

Exercise 3.11

Determine the stereochemical configurations of the chiral centers in the biomolecules shown below.

From left to right: dihydroorotate molecule, mevalonate molecule, (D)-erythrose molecule.

Exercise 3.12

Should the ( R ) enantiomer of malate have a solid or dashed wedge for the C-O bond in the figure below?

(R)-malate molecule. States: draw this bond (the bond between carbon and O H) as wedged or dashed to get R configuration.

Exercise 3.13

Using solid or dashed wedges to show stereochemistry, draw the ( R ) enantiomer of ibuprofen and the ( S ) enantiomer of 2-methylerythritol-4-phosphate (structures are shown earlier in this chapter without stereochemistry).

Solutions to exercises

Khan Academy video tutorial on the R-S naming system

in assigning r s configuration which among the following groups has highest priority

IMAGES

  1. Absolute Configurations Assigning R and S

    in assigning r s configuration which among the following groups has highest priority

  2. How to Determine the R and S configuration

    in assigning r s configuration which among the following groups has highest priority

  3. In assigning R

    in assigning r s configuration which among the following groups has highest priority

  4. Absolute Configurations Assigning R and S

    in assigning r s configuration which among the following groups has highest priority

  5. Solved www.10team Submit Question 1 of 22 Determine the

    in assigning r s configuration which among the following groups has highest priority

  6. Short Cut For Cahn Ingold Prelog Rules : Introduction to Assigning (R) and (S) Configuration

    in assigning r s configuration which among the following groups has highest priority

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COMMENTS

  1. Absolute Configuration: R-S Sequence Rules

    If there is branching, choose the branch that is higher in priority. If the two substituents have similar branches, rank the elements within the branches until a point of difference. After all your substituents have been prioritized in the correct manner, you can now name/label the molecule R or S.

  2. In assigning R

    In assigning R-S configuration −SO 3H group has highest priority. The decreasing order of priority is −SO 3H>−COOH>−CHO>−C 6H 5. Higher is the atomic number of the atom, higher is its priority. The atomic number of S is maximum. Hence, −SO 3H group has highest priority. Video Explanation Was this answer helpful? 0 0 Similar questions

  3. In assigning R-S configuration , which among the following groups has

    Which among the following functional groups has been given the highest priority while assigning R-S configuration asked Dec 8, 2021 in Chemistry by Niyajain ( 99.3k points) 0 votes

  4. Solved Which of these groups has the highest priority in R/S

    Question: Which of these groups has the highest priority in R/S configuration determination? a 1) b 2) c 3) d 4) e 5) Show transcribed image text Expert Answer 100% (18 ratings) Transcribed image text: Which of these groups has the highest priority in R/S configuration determination? a 1) b 2) c 3) d 4) e 5) Previous question Next question

  5. Solved 5 pts Question 9 When assigning R/S configuration

    Question: 5 pts Question 9 When assigning R/S configuration which of the following groups has the highest priority? Select the correct answer O carboxyl group hydroxyl group ethoxy group propyl group This problem has been solved! You'll get a detailed solution from a subject matter expert that helps you learn core concepts. See Answer

  6. In assigning R-S configuration which among the following groups has

    Thus, in assigning R-S configuration the group having highest priority is − S O 3 H. Thus, the correct option is (A) − S O 3 H. Note: The R-S configuration is also known as CIP rule because it was given by Cahn, Ingold and Prelog. When four groups or substituents are attached to the chiral carbon atom, they are ranked in the order of priority.

  7. In assigning R-S configuration , which among the following groups has

    In assigning R-S configuration , which among the following groups has highest priority ? ...

  8. In assigning RS configuration which among the following groups has

    For finding highest priority group CIP rule is followed According to this rule first priority is given to that compound whose atomic number is more than other If first atom is same then same thing is checked for next atom SO3H Sulphur atomic number 16 ...

  9. In assigning $R-S$ configuration which among the f

    In R-S configuration, priority sequence is decided by the atoms directly attached to the chiral carbon arranged in decreasing atomic number. From the given groups, sulphur (S) has the highest atomic number i.e., 16 therefore, it gets highest priority. Download Solution in PDF.

  10. In assigning R-S configuration which among the following groups has

    From the given groups, sulphur (S) has the highest atomic number i.e., 16 therefore, it gets highest priority. Questions from Organic Chemistry - Some Basic Principles and Techniques 1.

  11. Which among the following functional groups has been given the highest

    Which among the following functional groups has been given the highest priority while assigning R-S configuration A. `-C_ ... C_(2)H_(5)` D. `-CH_(3)` ... Cn has been given the hightest priority while assigning the R-S configuration The priority order is written for the following as

  12. How to Determine the R and S configuration

    Even if only one atom has a higher atomic number than the highest one on the other carbon, the group gets higher priority. So, one S beats N, O, F because it has a higher atomic number than the others individually. Carbon is not the only atom designated by R and S.

  13. In assigning R-S configuration, which among the following groups has

    In R-S configuration, priority sequence is decided by the atoms directly attached to the chiral carbon arranged in decreasing atomic number. From the given groups, sulphur (S) has the highest atomic number i.e., 16 therefore, it gets highest priority. Switch Flag Bookmark Advertisement Advertisement 19.

  14. PDF Priority Rules for Naming Chiral Centers

    number, the higher the priority.! Number the four atoms, or groups of atoms, such that "1" has the highest priority and "4" has the lowest priority. 2. If two or more of the atoms that are bonded directly to the chiral center are the same, then prioritize these groups based on the next set of atoms (i.e., atoms adjacent to the directly-

  15. 7.2: Naming chiral centers: the R and S system

    Rules for assigning an R/S designation to a chiral center. 1: Assign priorities to the four substituents, with #1 being the highest priority and #4 the lowest. Priorities are based on the atomic number. 2: Trace a circle from #1 to #2 to #3. 3: Determine the orientation of the #4 priority group.

  16. SOLVED:Assign the R and S configuration to the following:

    It is the are configuration because it is a clockwise for part C. We have these four groups attached to our, uh, center carbon Romy, and has the highest priority followed by these this to carbon chain than the metal. And then, lastly, is the hydrogen, just like in part a, the hydrogen, where the lowest priority group has to be on that hatched ...