The intermolecular oxidations of olefins with alcohols as nucleophile typically generate ketals, where as the palladium-catalyzed oxidations of olefins with carboxylic acids as nucleophile generates vinylic or allylic carboxylates. In case of diols, their reactions with alkenes typically generate ketals, whereas reactions of olefins bearing electron-withdrawing groups tend to form acetals.
Palladium-catalyzed intermolecular oxidations of dienes with carboxylic acids and alcohols as donors give 1,4-addition products. In the case of cyclohexadiene (Figure 4, A), Backvall found that stereochemical outcome of product was found to depend on concentration of LiCl. This reaction proceeds by first generating the Pd(OAc)(benzoquinone)(allyl) complex, through anti-nucleopalladation of diene with acetate as nucleophile. The absence of LiCl induces an inner sphere reductive elimination to afford the trans-acetate stereochemistry to give the trans-1,4-adduct. The presence of LiCl displaces acetate with chloride due to its higher binding affinity, which forces an outer sphere acetate attack anti to the palladium, and affords the cis-acetate stereochemistry to give the cis-1,4-adduct. Intramolecular oxidative cyclization: 2-(2-cyclohexenyl)phenol cyclizes to corresponding dihydro-benzofuran (Figure 4, B); 1-cyclohexadiene-acetic acid in presence of acetic acid cyclizes to corresponding lactone-acetate 1,4 adduct (Figure 4, C), with cis and trans selectivity controlled by LiCl presence.