Homochiral lithium amides for the asymmetric synthesis of β-amino acids
作者:Stephen G. Davies、Narciso M. Garrido、Dennis Kruchinin、Osamu Ichihara、Luke J. Kotchie、Paul D. Price、Anne J. Price Mortimer、Angela J. Russell、Andrew D. Smith
DOI:10.1016/j.tetasy.2006.05.008
日期:2006.7
Secondary homochiral lithium amides derived from α-methylbenzylamine undergo highly diastereoselective conjugate additions to a range of α,β-unsaturated esters. The corresponding β-aminoacids are readily liberated by successive N-debenzylation and ester hydrolysis, furnishing (R)-β-amino butyric acid, (R)-β-amino pentanoic acid, (S)-β-leucine, (R)-β-amino octanoic acid, (S)-β-phenylalanine, (S)-β-tyrosine
A synthesis of aziridine esters based on the cyclisation of amino selanyl esters induced by the selanyl group activation was developed with either the Meerwein salt or NBS. Twoasymmetricapproaches are proposed: the diastereoselective reductions of α-selanyl β-iminoesters derived from α-oxoesters, which lead to cis chiral aziridine esters 6 and 6′; and the diastereoselective conjugate additions of