Alkylaluminum halide catalyzed intramolecular ene reactions of 8-keto esters proceed in high yield to give cyclohexanols, via either a type I or type I1 process. Treatment of &keto ester 3 with MezAICl gives cis-fused ene adduct 5 in 67% yield. Similarly, 10 gives a 90% yield of 11 while treatment of 14 with Me3Al gives a 63% yield of 15. Treatment of 21 with MezAICl gives a 52% yield of a mixture of isomeric ene adducts 22 and 23. Treatment of ...
