Stereoselective Radical Addition to .ALPHA.-Methylenebutyrolactones by Indirect Electroreduction Catalyzed by a Nickel(II) Complex.
作者:Shigeko OZAKI、Eiki MATSUI、Hidenobu OHMORI
DOI:10.1248/cpb.45.198
日期:——
The addition of butyl radicals to β- and/or γ-disubstituted α-methylenebutyrolactones by a nickel(II) complex-catalyzed indirect electroreduction using equimolar amounts of butyl iodides and α-methylenebutyrolactones provides cis-(C-α) : (C-β)-trisubstituted lactones as the major product. The addition was successful because the present method to permits long lifetimes for the initial butyl radicals and decreases lifetimes of the final adduct radicals by selective reduction of these radicals.
2-Methylene-4-butyrolactones were conveniently synthesized by treatment of an aldehyde with 2-carboethoxyallyl(-ic) bromide and metallic tin (and aluminum) in good yields. Protolichesterinic acid was synthesized by employing the method.