Acid-Catalyzed Double-Cyclization Reactions of N, N-Dibenzylamino-acetaldehyde Dialkyl Acetals and Related Compounds: General Synthesis of 7,12-Dihydro-5//-6,12-methanodibenz-[c/]azocines and Related Compounds

Abstract

A number of N,N-dibenzylaminoacetaldehyde dialkyl acetals (1) double-cyclized in 70% perchloric acid or triflic acid (trifluoromethanesulfonic acid) to give good yields of 7,12-dihydro-5H-6,12-methanodibenz[c,f]azocines (2) even when a powerful electron-withdrawing substituent, for example a nitro group, was present on the benzene ring. Triflic acid treatment of a-dibenzylaminoketones (3) caused double-cyclization to give 12-substituted derivatives of 2. © 1986, The Pharmaceutical Society of Japan. All rights reserved.