The first catalytic,asymmetric alpha-additions of isocyanides. Lewis-base-catalyzed,enantioselective Passerini-type reactions

The first, catalytic, enantioselective alpha-additions of isocyanides to aldehydes have been demonstrated (Passerini-type reactions). The catalytic system of silicon tetrachloride and a chiral bisphosphoramide 5a provided high yields and good to excellent enantioselectivities for the addition of tert-butyl isocyanide to a wide range of aldehydes (aromatic, olefinic, acetylenic, aliphatic). Aqueous workup afforded the alpha-hydroxy tert-butyl amides, whereas methanolic quench followed by basic workup afforded the alpha-hydroxy methyl esters.