The stereochemical descriptors 'Erythro' and 'Threo' are frequently utilized to define diastereomers — Isomerism and Stereochemistry Chemistry Question
Question
The stereochemical descriptors 'Erythro' and 'Threo' are frequently utilized to define diastereomers possessing two adjacent chiral centers. In a standard 2D Fischer projection, which of the following spatial configurations correctly defines an 'Erythro' isomer?
💡 Solution & Explanation
In standard carbohydrate chemistry and classical stereochemistry, the 'erythro' stereochemical diastereomer is explicitly defined as the conformation where two similar functional groups on immediately adjacent stereocenters are drawn on the exact *same* side (left or right) of the vertical carbon backbone in a Fischer projection. The 'threo' isomer places them on *opposite* sides.