Partial and Chemoselective Reduction of Nitrites with Metal Diisobutyl-t-butoxyaluminum Hydrides

摘要

Recently,we have reported that a new class of reducing agents,metal diisobutyl-t-butoxyaluminum hydrides such as lithium diisobutyl-t-butoxyaluminum hydride(LDBBA),sodium diisobutyl-t-butoxyaluminum hydride(SDBBA),and potassium diisobutyl-t-butoxyaluminum hydride(PDBBA),the t-butoxy derivatives of DIBALH,are new effective partial reducing agents which can reduce various esters to aldehydes in high yields.Among them,LDBBA was especially effective for partial reduction of isopropyl esters to aldehydes usually in higher than 90% yield at 0 °C.Also,SDBBA and PDBBA were effective for partial reduction of common methyl and ethyl esters in very good yield(71-93%)at 0 °C.Accordingly,we decided to extend our investigation to the reduction of nitriles(Scheme 1)because partial reduction of nitriles into aldehydes is one of important and highly desirable means in organic synthesis,and a large number of reducing agents for this have been reported.