Metal and Activating Group Free C-4 Alkylation of Isoquinolines via a Temporary Dearomatization Strategy.

A simple method for the C-4 alkylation of isoquinolines is described using benzoic acid as a nucleophilic reagent and vinyl ketones as an electrophile. The reaction shows tolerance for substitution at C-3, and C-5-C-8 positions as well as allowing some variation of the vinyl ketone electrophiles. The products contain a carbonyl that can act as a synthetic handle for further manipulations giving esters, amines, or simple alkyl products.