Question

The letters ${}^{\prime }{D}^{\prime }$ or ${}^{\prime }{L}^{\prime }$ before the name of a stereoisomer of a compound indicate the correlation of configuration of that particular stereoisomer. This refers to their relation with one of the isomers of glyceraldehyde. Predict whether the following compound has ${}^{\prime }{D}^{\prime }$ or ${}^{\prime }{L}^{\prime }$ configuration.

Answer 1

All those compounds which can be chemically correlated to $D-(+)-$isomer of glyceraldehyde are said to have $D-$configuration whereas those which can be correlated to $L-(-)-$isomer of glyceraldehyde are said to have $L-$configuration. In the $L(-)$ isomer $-OH$ group located on the penultimate carbon (last chiral carbon) in fischer projection is on the left hand side as shown here.