A Remarkable Effect of Bases on the Catalytic Radical Addition of Cyanoacetates to Alkenes Using a Mn(II)/Co(II)/O2 Redox System

Abstract

Abstract A remarkable addition effect of bases, like AcOK, was observed in the radical addition of cyanoacetates to alkenes catalyzed by a Mn(II)/Co(II)/O2 redox system. Thus, a carbon radical from ethyl cyanoacetate could be catalytically generated by adding AcOK to the Mn(II)/Co(II)/O2 redox system, even at room temperature, and the resulting carbon radical readily added to 1-octene to give an adduct, ethyl 2-cyanodecanoate, in good yield, while no reaction took place at all in the absence of AcOK. Ethyl cyanoacetate added smoothly to a variety of alkenes under mild conditions in the presence of a base to lead to the corresponding adducts in fair-to-good yields. It is reasonable to assume that the base added accelerated the deprotonation from a transient carbocation intermediate generated by the one-electron oxidation of ethyl cyanoacetate by the Mn(III) ion. This method provides an alternative route to alkylation of cyanoacetates under mild conditions.