BF3•Et2O catalyzed diastereoselective nucleophilic reactions of 3-silyloxypiperidine N,O-acetal with silyl enol ether and application to the asymmetric synthesis of (+)-febrifugine

The asymmetric BF3 center dot Et2O catalyzed nucleophilic reactions of 3-silyloxypiperidine N,O-acetal 10 with silyl enol ethers derived from ketones are described. (+)-Febrifugine 1, an antimalarial alkaloid, was successfully synthesized based on this nucleophilic substitution. In addition, N,O-acetal 10 was synthesized from L-benzyl glutamate in 11 steps. (C) 2009 Elsevier Ltd. All rights reserved.