Rhodium-Catalyzed Tandem Isomerization-Allylation: From Diallyl Carbonates to α-Quaternary Aldehydes

Article abstract of DOI:10.1021/acscatal.9b04128

We report a Rh-catalyzed tandem isomerization-allylation sequence for the generation of α-quaternary aldehydes, starting from unsymmetrical diallyl carbonates. This reaction features a highly selective oxidative addition of the rhodium catalyst, leading to the discrimination of electrophilic and nucleophilic elements of various diallyl carbonates. A rhodium-enolate and an allyl electrophile are produced catalytically in situ in a controlled fashion, enabling this reaction to occur with high chemoselectivity and regioselectivity. Mechanistic investigation via reaction progress kinetic analysis uncovered second-order kinetics in rhodium, suggesting that an unexpected dual metal pathway may be operative for the key C-C bond-forming step.