Rapid Synthesis of anti‐1,3‐Diamino‐4‐phenylbutan‐2‐ol Building Blocks via a Three‐Component Oxyhomologation and a Two‐Component Reducing System.

<italic>N</italic>1‐substituted derivatives of <italic>anti</italic>‐(2<italic>R</italic>,3<italic>S</italic>)‐1,3‐diamino‐4‐phenylbutan‐2‐ol are important building blocks for the synthesis of therapeutically important molecules. We describe a simple protocol that allows transformation of <italic>N,N</italic>‐dibenzyl‐L‐phenylalaninal into such compounds in only two steps. The first step is a fully stereoselective three‐component MAC (Masked Acyl Cyanide) oxyhomologation reaction implicating different amines to give a panel of ten <italic>N,N</italic>‐dibenzyl‐<italic>O</italic>‐<italic>tert</italic>‐butyldimethylsilyl‐protected <italic>anti</italic>‐(2<italic>S</italic>,3<italic>S</italic>)‐allophenylnorstatin amides. The second step is a carbonyl‐activated hydride deprotection/reduction protocol using trimethylsilyl chloride and lithium aluminium hydride; the one‐pot two‐component system is more efficient than the alternative approach of isolating the deprotected amide intermediate before reduction. [ABSTRACT FROM AUTHOR]