Parallel kinetic resolution of tert-butyl (RS)-3-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 3-alkyl-cispentacin derivatives

Stephen G. Davies*, A. Christopher Garner, Marcus J.C. Long, Andrew D. Smith, Miles J. Sweet, Jonathan M. Withey

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)

Abstract

The double mutual kinetic resolution of tert-butyl (RS)-3-benzyl-cyclopentene-1-carboxylate with a 50:50 mixture of lithium (RS)-N-benzyl-N-α-methylbenzylamide and lithium (RS)-N-3,4-dimethoxybenzyl-N-a-methylbenzylamide gives, after protonation with 2,6-di-tert-butylphenol, a 50:50 mixture of the readily separable N-benzyl-(1SR,2RS,3RS,αRS)- and N-3,4-dimethoxybenzyl-(1SR,2SR,3SR,αSR)-β-amino esters in >98% de in each case. This product distribution indicates that these amides react at very similar rates and with no mutual interference to furnish readily separable products, and are thus ideal for parallel kinetic resolution. The efficient parallel kinetic resolution (E > 65) of a range of tert-butyl (RS)-3-alkyl-cyclopentene-l-carboxylates with a pseudoenantiomeric mixture of homochiral lithium (S)-N-benzyl-N-α-methylbenzylamide and lithium (R)-N-3,4-dimethoxybenzyl-N-α-methylbenzylamide gives, after separation and N-deprotection, a range of carboxylate protected 3-alkyl-cispentacin derivatives in >98% de and >95% ee.

Original languageEnglish
Pages (from-to)3355-3362
Number of pages8
JournalOrganic and Biomolecular Chemistry
Volume2
Issue number22
DOIs
Publication statusPublished - 21 Nov 2004

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