Reduction of aldimines

S. K. Srinivasan, S. Narasimhan u. N. Venkatasubramanian, Adv. Catal. [Proc. - Natl. Symp. Catal.], 7th, 315-319 (1985) . .Selective Reduction of Aldimines by Formic Acid in the Presence of RhH(PPhj)4 . 

The sodium reduction has been extended to esters. Thus, methyl 2-ethylmercapto-5-ethyIthiophen-3-carboxylate (128) yielded the amide (129) as the main product upon treatment with four equivalents of sodium in liquid ammonia. Reduction of aldimines such as (118) with LiAlH4 gives thenylamines such as (130) in high yield, which can be condensed... 

Secondary Amines.—The reduction of imines to the corresponding secondary amines can be effected by various methodologies. New additions are the sodium triacyloxyborohydrides (easily obtainable from sodium borohydride and AT-acyl derivatives of optically active amino-acids), which are used for the asymmetric reduction of cyclic imines. Also now available is a highly stereoselective reduction of N-benzylimines derived from substituted cyclohexanones, with alkali-metal borohydrides, in particular L-selectride. A fiuther addition is the first report of the reduction of aldimines by hydrogen transfer from propan-2-ol,... 

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