Asymmetric Synthesis of So-Called "Fumarizine" Isomer

Abstract

A so-called "fumarizine" isomer, (R )-1-(6-methoxy-2, 3-methylenedioxybenzyl)-2-methyl-6, 7-methylenedioxy-1, 2, 3, 4-tetrahydroisoquinoline was asymmetrically synthesized via the stereoselective reduction of the corresponding iminium ion possessing a chiral auxiliary, which was obtained by the Bischler-Napieralski cyclization of N-[(R)-1-phenylethyl]-N-[2-(3, 4-methylenedioxyphenylethyl)] -2-(6-methoxy-2, 3-methylenedioxyphenyl) acetamide. Since the spectral data for the synthetic compound were different from those reported for the natural product, the structure of fumarizine must be reexamined.