Bicyclo[3.3.1]nonanes as synthetic intermediates. Part 19.1 Asymmetric cleavage of ω-azabicyclo[3.n.1]alkan-3-ones at the ‘fork head’

Abstract

Asymmetric cleavage of ω-azabicyclo[3.n.1]alkan-3-ones was achieved by asymmetric deprotonation at the ‘fork head’ ketone system with Koga’s chiral base and subsequent ozonolysis of the resulting chiral silyl enol ether to give the cis-α,α′-disubstituted piperidine, pyrrolidine and hexahydroazepine, respectively, in high enantiomeric excess.