Pd/Rh Dual Catalysis: Tandem Isomerization–Allylation to Access Α-Quaternary Carbonyl Compounds

A dual metal approach enables the use of unsymmetrical diallyl carbonates as viable enolate precursors for allylic alkylation reactions, allowing facile access to various alpha-quaternary allylated aldehydes and ketones. This methodology features a regioselective Pd-catalyzed decarboxylative oxidative addition, forming an electrophilic Pd pi-allyl species and releasing an allylic alkoxide, which undergoes a Rh-catalyzed isomerization to an enolate in situ. Recombination of the Pd pi-allyl species and Rh-enolate nucleophile then affords the alpha-quaternary carbonyl compound.