Consider the Fischer projection of the following sugar...

Consider the Fischer projection of the following sugar molecule: O || CH H-2-OH H-3-OH H-4-OH CH2OH The absolute configuration at C2, C3, and C4 are a) 2R, 3R, 4R b) 2S, 3S, 4S c) 2S, 3R, 4R d) 2R, 3S, 4S

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Transcript

00:01 Hello students, in this question we have to tell the absolute configuration of these stereo centers.

00:06 Let's name them as c2, c3 and c4.

00:10 Now let's draw our c2 carbon here.

00:14 It will have two groups like this hydroxyl and hydrogen will be considered above the plane and the cho group and this below the plane carbon atom will be considered as the below the plane.

00:29 Hydrogen will have the last priority according to cip rules.

00:33 Hydroxyl group will get the first priority.

00:36 Now in these two carbon atoms we can see that this carbon is connected to two oxygen atoms whereas this is connected to only one so this will get the higher priority.

00:48 So this will be the order of priority.

00:50 Now if we observe the rotation from 1 to 3 its configuration will be r.

00:57 Therefore the second carbon will have the r configuration.

01:01 Now let's draw the c3.

01:03 It will have the hydroxyl group here, hydrogen atom here and here.

01:11 It will have a carbon atom connected to one oxygen and one cho and one hydrogen and here will be one more carbon that will be connected to one oh group, one hydrogen and one ch2oh group.

01:28 Now let's assign the priorities.

01:31 This hydrogen will get the fourth priority, hydroxyl group will get the first priority...

Question

Consider the Fischer projection of the following sugar molecule: O || CH H-2-OH H-3-OH H-4-OH CH2OH The absolute configuration at C2, C3, and C4 are a) 2R, 3R, 4R b) 2S, 3S, 4S c) 2S, 3R, 4R d) 2R, 3S, 4S

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