Synthesis of α2,2,β3‐Diamino Acids by Double Stereodifferentiation Aldol Addition of Oxazolidinone Enolates to N‐(tert‐Butylsulfinyl) Imines

A novel application of Seebach's “SRS” synthetic principle works efficiently when conformationally restrained trisubstituted chiral α2,2,β3‐diamino acids are synthesized by double stereoinduction reactions of chiral oxazolidinone enolates with N‐sulfinyl aldimines. Two stereoisomers were isolated in a form of 1′‐(sulfinylamino)oxazolidinones and bicyclic 1H,3H‐imidazo[1,5‐c]oxazole‐1,5(6H)‐diones, from which the α2,2,β3‐diamino acids are obtained by selective deprotection methodologies. Among a variety of highly functionalized diamino acids, this highly diastereoselective protocol provides a synthetic route for yet unreported C‐glycosyl and α‐nucleoside diamino acids. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)