Transition Metal-Free Selective Aerobic Olefination of Methyl N-Heteroarenes with Alcohols
By performing the reactions in the presence of adequate amount of air and a suitable base,selective olefination of methyl N-heteroarenes with alcohols can be effectively achieved without using any external catalyst.Control experiments re-vealed that,with adequate air,base can promote the aerobic oxidation of alcohols almost completely to carbonyl intermediates,which then condense with the methyl N-heteroarenes to afford the alkenyl N-heteroarene products.As the reaction is performed with adequate amount of air and a lower loading of the base at a lower temperature than that of the alkylation reaction,the generated alkenyl N-heteroarenes cannot be transfer hydrogenated to the alkylated products by the remained small amount of alcohol in the reaction mixture,which leads to a high selectivity of the olefination reaction.This method is thus a practical way for preparation of the alkenyl N-heteroarenes,being a complementary method to previous transition metal-free C-alkylation reaction of methyl N-heteroarenes with alcohols in the presence of small amount of air.
NETL
NSTL
万方数据
