Chiral glycine cation equivalents: N-acyliminium species derived from diketopiperazines
作者:Steven D. Bull、Stephen G. Davies、A. Christopher Garner、Michael D. O'Shea、Edward D. Savory、Emma J. Snow
DOI:10.1039/b207457p
日期:2002.11.13
Studies towards a N,N′-bis(p-methoxybenzyl)diketopiperazine asymmetric glycine cation equivalent for the synthesis of homochiral α-amino acids are described. The oxidation of enolate 3 with molecular oxygen provides either a mixture of hydroxylated diketopiperazines 7 and 8 or trione 10 depending upon the reaction conditions. The nucleophilic reduction of trione 10 and the reaction of acetoxy N-acyliminium ion precursors 5 and 6, derived from 7 and 8, with allyltrimethylsilane and boron trifluoride etherate is examined and a model for the stereoselectivity observed in these additions is presented.