MCQ
Esterification (shown below) is a reaction converting a carboxylic acid to its ester.  It involves only the carbonyl carbon. Esterification of $(-) $ lactic acid with  methanol  yields $(+)$ methyl acetate. Assuming that there are no side reactions,  what is true about this reaction ?
  • A
    An $S_{N^2}$ process has occurred, inverting the absolute configuration of the  chiral center
  • B
    An $S_{N^1}$ reaction at the chiral center has inverted the optical rotation
  • C
    A diastereomer has been produced; diastereomers have different physical  properties including optical rotation
  • Optical rotation is not directly related to absolute configuration, so the change in  sign of rotation is merely a coincidence

Answer

Correct option: D.
Optical rotation is not directly related to absolute configuration, so the change in  sign of rotation is merely a coincidence
d
$(d)$ Chiral center is not affected during the reaction so change in sign of rotation  is merely a coincidence.

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