ASIAN JOURNAL OF ORGANIC CHEMISTRY, v. 8, No. 9, Page. 1617-1620
Abstract
The synthesis of substituted benzo[a]quinolizidines via aza-Michael addition of tetrahydroisoquinolines to alkyl vinyl ketones, followed by oxidative Mannich cyclization, is described. Various Michael adducts are easily prepared, and subsequent DDQ-mediated oxidations stereoselectively afford the corresponding azacycles efficiently. Furthermore, the one-pot aza-Michael/oxidative Mannich process gave benzo[a]quinolizidines, thus providing a metal-free and practical synthetic route to N-heterocyclic building blocks.