Radical addition of ketones and cyanide to olefins: Via acid catalyzed formation of intermediate alkenyl peroxides

Abstract

A Brønsted acid catalyzed method was developed for the synthesis of γ-cyanoketones from sulfonyl cyanides, olefins and ketones. The reaction is believed to proceed via intermediate formation of alkenyl peroxides by condensation of ketones with tert-butylhydroperoxide. These unstable compounds decompose by homolytic O-O bond cleavage, generating ketone-derived radicals which add to the olefins and generate the final products after reaction with the sulfonyl cyanide, thereby forming two new C-C bonds. A range of different ketones and olefins can be used, including steroidal ketones and simple alkyl olefins. The products can be further transformed to substituted lactones and piperidines, including a tetracyclic one. This reaction can thus be utilized to gain access to complex molecules from simple starting materials in only a few synthetic steps.