Silver-catalyzed asymmetric amination of silyl enol ethers

Catalytic amination of silyl enol ethers with azo diester compounds was inv estigated. It was shown that Cu(OTf)(2) or AgOTf had high catalytic activit y and that AgOTf was the most efficient among the catalysts tested in the r eactions. In asymmetric reactions, the AgClO4-BINAP system showed high enan tioselectivity. In a mixture of toluene or mesitylene and THF, silyl enol e thers reacted with dibenzyl azodicarboxylate (DBnAD) smoothly to afford the corresponding amination adducts in excellent yields with up to 86% ee.