Alkylation of remote non-activated δ-carbon atoms:: Addition of δ-carbon radicals, generated by 1,5-hydrogen transfer in alkoxy radical intermediates, to activated olefins

A free radical introduction of a functionalized alkyl chain onto remote non-activated delta-carbon atoms (Michael type alkylation) has been achieved. Photolysis of suitable alkyl nitrites involves generation of delta-alkyl radicals and in the presence of radicophilic olefins, intermolecular addition takes place and affords delta-alkylated products in 36-80% yields. delta-Alkylation is also achieved in the reaction of alkyl benzenesulfenates with tributyltin hydride (TBTH) in the presence of activated olefins and introduction of a functionalized alkyl chain involves alkoxy and delta-carbon radicals. Products with functionalized alkyl chains were obtained io 36-86% yields. delta-Alkylation of alkyl benzenesulfenates also occurs in the reaction with hexabutylditin lit the presence of activated olefins. (C) 1999 Elsevier Science Ltd. All rights reserved.