Reactions of methylated cyclopropanes and olefins with chloroplatinic acid II. Monoacylation and the formation of β,γ-unsaturated carbonyl complexes of platinum dichloride

Upon reaction with chloroplatinic acid in acid anhydride solvents, several methyl-substituted cyclopropanes and olefins form platinum dichloride adducts of β,γ-unsaturated carbonyls in which the ligand is bound to platinum through both the olefin π-system and a lone pair on the carbonyl oxygen. The cyclopropane reactions are shown to proceed initial isomerization to an olefin, followed by acylation and proton loss. The stereochemistry of the products is shown to be dependent upon the substitution on the carbons α and β to the carbonyl, and in the case where both the α- and β-carbons are methyl-substituted a single conformation cf the product is isolated.