Sodium borohydride in carboxylic acid media: a phenomenal reduction system

The union of sodium borohydride and carboxylic acids has yielded an amazing ly versatile and efficient set of reducing reagents, These acyloxyborohydri de species reduce and N-alkylate indoles, quinolines, isoquinolines, relate d heterocycles, imines, enamines, oximes, enamides, and similar functional groups. They reduce amides and nitriles, aryl alcohols and ketones, aldehyd es in the presence of ketones, and beta-hydroxyketones to 1,3-diols stereos electively, This reagent is also extraordinarily useful for the N-alkylatio n of primary and secondary amines with aldehydes and ketones in a novel red uctive amination process.