Ruthenium Tetroxide Oxidation of 1-Azabicycloalkan-2-ones

Abstract

The ruthenium tetroxide (RuO₄) oxidation of 1-azabicycloalkan-2-ones was investigated. The oxidation of quinolizidin-4-one (4), indolizidin-3-one (9), pyrrolizidin-3-one (11) and tetrahydro-1H, 3H-pyrrolo [1, 2-c] oxazol-3-one (12) occurred at the bridgehead tertiary carbon atom and afforded the corresponding hydroxy compounds (from 11 and 12) or the imidobutyric acid derivatives (from 4 and 9). This regioselectivity is contrary to the general situation in the oxidation of N-acyl cyclic amines. However, 1-azabicyclo [4.2.0] octan-8-one (17) was oxidized at the secondary carbon atom to give the 2, 8-dione (18).