A gallium hydride reagent, HGaCl2, was found to act as a radical mediator. Treatment of alkyl halides with the gallium hydride reagent, generated from gallium trichloride and sodium bis(2-methoxyethoxy)aluminum hydride, provided the corresponding reduced products in excellent yields. Radicalcyclization of halo acetals was also successful with not only the stoichiometric gallium reagent but also a
New Method for the Preparation of an Active Manganese Species and its Use for Radical Cyclization Reactions
作者:Jun Tang、Hiroshi Shinokubo、Koichiro Oshima
DOI:10.1055/s-1998-1897
日期:1998.10
Reduction of Li2MnCl4 with magnesium in THF afforded a fairly active manganese species which readily initiated radical cyclization of 2-iodoethanal allylic acetals at room temperature. The corresponding 2-bromoethanal acetals also provided the same cyclized products upon treatment with the activated manganese reagent at reflux in THF.