A Fischer projection of 4-bromo-2-chloro-3-hydroxypentanoic acid has the vertical chain, top to bottom: COOH, C2, C3, C4, C5 (CH3). The groups on the left of C2, C3 and C4 are Cl, OH and Br respectively, and on the right of each is H. Which statements are correct?

C2 and C3 have the same CIP descriptor.

JEE Advanced levelOne or more correct optionsDifficulty 3 of 3st046

A Fischer projection of 4-bromo-2-chloro-3-hydroxypentanoic acid has the vertical chain, top to bottom: $COOH$ , C2, C3, C4, C5 ( $CH X_{3}$ ). The groups on the left of C2, C3 and C4 are $Cl$ , $OH$ and $Br$ respectively, and on the right of each is $H$ . Which statements are correct?

C2:

Cl > COOH > C3 > H

(

COOH

has

(O, O, O)

, C3 has

(O, C, H)

Cl

(left)

\to

COOH

(top)

\to

C3 (bottom) is clockwise;

H

is horizontal, so reverse:

S

. C3:

OH > C4

(Br, C, H) > C2

(Cl, C, H) > H

OH

(left)

\to

C4 (bottom)

\to

C2 (top) is anticlockwise; reverse:

R

. C4:

Br > C3 > CH X_{3} > H

;

Br

(left)

\to

C3 (top)

\to

CH X_{3}

(bottom) is clockwise; reverse:

S

. So the compound is

(2 S, 3 R, 4 S)

: B and C are correct; A is wrong and C2 and C3 differ (D wrong).