Meyers Asymmetric Alkylation – Asymmetric Synthesis

Carboxylic acids can be converted into chiral oxazolines which act as effective auxiliaries in diastereoselective alkylation of the enolate equivalents. The formation of Z-azaenolate along with the complexation of the electrophile, methyl chloride, with the lithium causes the attack to occur from underneath.The presence of a bulky group like phenyl also directs the electrophilic attack to take place at the bottom, therefore providing a single diastereoisomer of product and ultimately a single enantiomer of alkylated carboxylic acid.

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A. I. Meyers and E. D. Mihelich, Angew. Chemie Int. Ed. English, 1976, 15, 270–281.