Studies on 1-Azabicyclo Compounds. XXVII. Synthesis of Ten-membered Ring Amines from 1-Oxo-, 9a-Benzyl-, and 9a-Benzyl-1-oxo-quinolizidine

Abstract

The Stevens rearrangement of the N-benzyl bromide (VII), derived from 1-oxoquinolizidine (V), afforded 9a-benzyl-1-oxoquinolizidine (VIII). Reduction of the methiodides (VI and IX) of V and VIII with sodium amalgam gave the ten-membered aminoketones (XII and XIII), respectively. The yield of XIII was much more excellent than that of XII, because of the influence of the C₉a-benzyl substituent in IX. The C₉a-benzyl substituent, however, produced little effect on the reductive cleavage in the Birch reduction of IX leading to XIII and XV in comparison with that of VI leading to XIV, though 9a-benzylquinolizidine methiodides (XIa and XIb) furnished the ten-membered amine (XVI) in considerable yields.