Aminoborohydrides .9. Selective reductions of aldehydes, ketones, esters, and epoxides in the presence of a nitrile using lithium N,N-dialkylaminoborohydrides

A series of competitive reductions of several functional groups was carried out in the presence of aromatic and aliphatic nitriles using lithium N,N-dimethylaminoborohydride (LiMe(2)NBH(3)) or Lithium Pyrrolidinoborohydride (LiPyrrBH(3)) as the reducing agents. Both LiMe(2)NBH(3) and LiPyrrBH(3) cleanly and quantitatively reduced aldehydes, ketones, esters, and epoxides in the presence of the nitriles to give the corresponding reduction products in yields ranging from 85 to 98%. In no case was the nitrile reduced: no products arising from the reduction of nitriles were detected by GC analysis. Two difunctional nitriles were also reduced to give complete reduction of the more active functional group with no reduction of the nitrile. (C) 1997, Elsevier Science Ltd. All rights reserved.