The effect of base and additive on the alkylation of methyl hippurate.
作者:John M. McIntosh、Rasiah Thangarasa、David J. Ager、Benxin Zhi
DOI:10.1016/s0040-4020(01)88213-2
日期:1992.1
Contrary to a published report, C-alkylation of methylhippurate requires two equivalents of base. The choice of additive (TMEDA or HMPA) influences the result. Deuteration of the enolate gives results which depend on both the deuterium source and the nature of the additive.
Synthesis of homochiral l-(S)-tert-leucine via a lipase catalysed dynamic resolution process
作者:Nicholas J. Turner、James R. Winterman、Raymond McCague、Julian S. Parratt、Stephen J.C. Taylor
DOI:10.1016/0040-4039(94)02408-4
日期:1995.2
Lipozyme® (Mucor miehei) in toluene containing n-butanol and a catalytic amount of triethylamine resulted in a 94% yield of (S)-N-benzoyltert-leucine butyl ester 9 (99.5% e.e.). Subsequent two step hydrolysis (Alcalase® followed by 6N HCl, reflux) yielded homochirall-(S)-tert-leucine 1.