Tandem cyclization-[3+3] cycloaddition reactions of 2-alkynylbenzaldoxime: synthesis of fused 1,2-dihydroisoquinolines

Tandem cyclization-[3+3] cycloaddition of 2-alkynylbenzaldoximes with dimethyl cyclopropane-1,1-dicarboxylate co-catalyzed by AgOTf and Yb(OTf)(3) is described, which provides an useful method for the synthesis of tetrahydro-1,2-oxazine fused 1,2-dihydroisoquinolines. (C) 2008 Elsevier Ltd. All rights reserved.