Reaction of Methyl 1-(2-Bromoisobutyryl)cyclopentane-carboxylate and 3-(1-Bromocyclopentyl)-2,2-dimethyl-3-oxo-propionate with Zinc and Aromatic Aldehydes

Methyl 1-(2-bromoisobutyryl)cyclopentanecarboxylate and 3-(1-bromocyclopentyl)-2,2-dimethyl-3-oxopropionate react with zinc and aromatic aldehydes to afford 8-aryl-9,9-dimethyl-7-oxaspiro[4.5]decane-6,10-diones and 10-aryl-7,7-dimethyl-9-oxaspiro[4.5]decane-6,8-diones, respectively.