Allenes and Acetylenes. XXIV. Synthesis of alpha-Allenic Amines by Organocuprate Reactions of Acetylenic Aminoethers.

Abstract

Tertiary .alpha.-allenic amines [monoamine oxidase inhibitors which can be used in the treatment of depression] are formed in good yields in reactions of acetylenic aminoethers with an organocuprate reagent, derived from butylmagnesium bromide and 5-20% of CuI, in tetrahydrofuran (THF) or THF-diethyl ether 3:1. The overall reduction reaction proceeds through an organometallic intermediate which is protonated on work-up. Primary and tertiary .alpha.-allenic amines are formed in moderate to good yields in 1,3-substitution reactions (SN2'') of acetylenic aminoethers with organocuprates in diethyl ether. The organocuprate reagents are derived from methylmagnesium or benzylmagnesium halide and 10% of CuI or CuBr. The choice of solvent in these allene-forming reactions is of crucial importance in steering the reactions in 1 of the 2 directions.