Question

Hello, I am reviewing my chemistry problems and need someone to draw me the structure + stereochemistry of the following:

1. (2R,3S) and (2S,3R) erythro-2,3-dibromo-3-phenylpropanoic acid

2. 2R, 3R) and (2S, 3S) threo-2,3-dibromo-3phenylpropanoic acid

3. Structure and stereochemistry of a mixture of both eryhtro and threo-2,3-dibromo-3phenylpropanoic acid

Please include all mechanisms that show how you obtain the different stereoisomer! (please show the stereochemical outcome of a brominum ion intermediate versus a carbocation intermediate versus a four atoms concerted transition state)

Answer 1

when both hydrogen and both bromine are in same side in fisher projection is known as erythro from

when both hydrogen and both bromine are in opposite  side in fisher projection is known as ethreo from