ASYMMETRIC-SYNTHESIS OF ANTI-ALPHA-ALKYL-BETA-AMINO ACIDS

Journal article

An investigation into the asymmetric induction accompanying alkylations of enolates derived from the highly diastereoselective conjugate addition of lithium (R)-N-benzyl-N-α-methylbenzylamide (R)-1 to crotonate and cinnamate esters has been performed. The access to different enolate geometries afforded by the conjugate addition process and subsequent enolate regeneration by deprotonation of the β-amino ester conjugate adducts enabled two disparate sets of selectivity data to be compiled. Although both approaches furnished predominantly anti-α-alkyl-β-amino esters, the two-step procedure proved to be considerably more selective. Several factors which play a major role in determining the alkylation selectivity are identified, including the cooperative influence of the α-methylbenzylamino stereocentre. Since debenzylation and hydrolysis of the alkylated products was straightforward, this methodology provides a direct route to anti-α-alkyl-β-amino acids in homochiral form.

Authors: Davies, S; Walters, I

• Publication status: Published
• Journal: JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1
• Volume: 9
• Issue: 9
• Pages: 1129-1139
• Publication date: 1994-05-07
• DOI: 10.1039/p19940001129
• EISSN: 1364-5463
• ISSN: 0300-922X