Silver-catalyzed asymmetric amination of silyl enol ethers

Abstract

Catalytic amination of silyl enol ethers with azo diester compounds was investigated. It was shown that Cu(OTf)2 or AgOTf had high catalytic activity and that AgOTf was the most efficient among the catalysts tested in the reactions. In asymmetric reactions, the AgClO4-BINAP system showed high enantioselectivity. In a mixture of toluene or mesitylene and THF, silyl enol ethers reacted with dibenzyl azodicarboxylate (DBnAD) smoothly to afford the corresponding amination adducts in excellent yields with up to 86% ee.Key words: amination, amino acid, asymmetric synthesis, chiral catalyst, silver.