6,6,8-Trimethylspiro[2.5]oct-7-en-4-one (2) and 6,6-dimethyl-8-methylenespiro[2.5]octan-4-one (3) undergo homoconjugateaddition with the anion derived from isophorone and with morpholine; the reactions of (3) are much more rapid than those of (2), reflecting greater spiroactivation in the case of (3).