Metal-free, visible-light-promoted decarboxylative alkylation of Baylis-Hillman acetates with N-(acyloxy)phthalimides

A visible-light-promoted decarboxylative alkylation of Baylis-Hillman acetates with N-(acyloxy)phthalimides to access trisubstituted alkyl acrylates under metal-free and mild reaction conditions was developed. A variety of N-(acyloxy)phthalimides derived from structurally diverse primary, secondary and tertiary aliphatic carboxylic acids could all smoothly convert to structurally diverse alkyl acrylates in this protocol. Interestingly, aliphatic carboxylic acids and acrylic esters derived from Baylis-Hillman acetates bearing a smaller steric structure show better stereoselectivity of the E configuration. This work offers an economic and easily handled approach to C(sp2)-C(sp2) and C(sp3)-C(sp3) bond formation in one step. Moreover, this protocol could be applied to the late-stage functionalization of natural products.

Automated summary

A metal-free and mild approach for the synthesis of trisubstituted alkyl acrylates was developed using visible-light-promoted decarboxylative alkylation of Baylis-Hillman acetates with N-(acyloxy)phthalimides. Various N-(acyloxy)phthalimides derived from primary, secondary, and tertiary aliphatic carboxylic acids smoothly converted to structurally diverse alkyl acrylates in this protocol. Interestingly, better stereoselectivity of the E configuration was observed for aliphatic carboxylic acids and acrylic esters derived from Baylis-Hillman acetates with smaller steric structure. This study provides an economic and easily-handled method for C(sp2)-C(sp2) and C(sp3)-C(sp3) bond formation, and can be applied to late-stage functionalization of natural products.