Reaction of Di-s-butoxyborane in Tetrahydrofuran with Selected Organic Compounds containing Representative Functional Groups. Catalytic Effect of Tetraalkoxyborate on the Reaction of Dialkoxyborane

摘要

The approximate rate and stoichiometry of the reaction of excess di-s-butoxyborane with selected organic compounds containing representative functional groups under standardized conditions (tetrahydrofuran, 25℃) were examined in order to define the characteristics of the reagent for selective reductions. And the catalytic effect of lithium tetra-s-butoxyborate on the reaction of di-s-butoxyborane was also studied in order to increase the utility of this reducing system. Di-s-butoxyborane reacts only with simple aldehydes. However the addition of 2.5 mole % of lithium tetra-s-butoxyborate shows the tremendous rate enhancement of reaction for aldehydes, ketones, anhydrides, acid chlorides, lactones, and epoxides. This catalytic effect is assumed to in situ formation of lithium trialkoxyborohydride.