92053-23-1Relevant academic research and scientific papers
Asymmetric Synthesis of 2-Alkylalkanoic Acids via Alkylation of Chiral Amide Anions
Guoqiang, Lin,Hjalmarsson, Mats,Hoegberg, Hans-Erik,Jernstedt, Karen,Norin, Torbjoern
, p. 795 - 802 (2007/10/02)
Acylation of (S)-proline methyl ester (2) gave amide ester 3 (R1=alkyl), which on reaction with methylmagnesium iodide furnished the tertiary alcohol 4.Alkylation of the dianion from this yielded mainly one diastereomer of the amide 5, which on acid hydrolysis gave the chiral 2-alkylalkanoic acid 6 in 75-90 percent e.e. and 55-82 percent chemical yield from the hydroxyamide 4.The latter compound could be recovered from the hydrolysate with preserved optical purity via acylation without isolation of the tertiary prolinol 7.The diastereomeric mixture of amides 5' and 5" could be separated by column chromatography leading to the acid 6 in very high optical purity.
