Facile Reduction of Carboxylic Acid Salts to Aldehydes by Boron Hydrides Thexylbromoborane-Dimethyl Sulfide and 9-Borabicyclo [3.3.1]nonane

摘要

New methods of the reduction of carboxylic acid salts to aldehydes with 2 equiv of thexylbromoborane-dimethyl sulfide (ThxBHBr· SMe2) or 9-borabicyclo[3.3.1]nonane (9-BBN) are described. Both these reagents provide the corresponding aldehydes from various as sodium and lithium salts of carboxylic acids in high yields both at room temperature. Such facile reductions are explained as the simple substitution for the bromo group of ThxBHBr by a carboxylate to form thexyl(acyloxty)borane followed by reduction with excess reagent and the formation of an ate complex followed by reduction with excess 9-BBN.