Tandem-Michael addition of 1-cyanoenamines to cyclohexenones. A new access to bicyclo[2.2.2]octanones

Article abstract of DOI:10.1055/s-1991-26398

Bicyclo[2.2.2]octane-2,5-diones 5 are easily obtained via tandem Michael addition of 2-(N-methylanilino)acrylonitrile (2) with deprotonated cyclohexenones I. The reaction is highly anti-stereoselective with respect to substituents on C-4 and C-5 of the cyclohexenone and is blocked by disubstitution on C-4. 6-Acylbicyclo[2.2.2]octan-2-ones 25 are obtained by tandem Michael addition of deprotonated 2-(N-methylanilino)but-2-enonitrile (18) with cyclohexenone and subsequent protonation or alkylation. Both reactions gave lower yields or even failed with cyclopentenone and cycloheptenone.