Enantiomerically pure, crystalline 'anti'-aldols from N-acylbornanesultams: Aldolization and structure of intermediate t-butyldimethylsilyl-N,O-ketene acetal

Article abstract of DOI:10.1016/S0040-4039(00)71218-4

O-Silylation of N-propionylsultam 1 provides pure Z O-silyl-N,O-ketene acetal 2 which undergoes Lewis acid promoted addition of aromatic and aliphatic aldehydes to give diastereomerically pure, crystalline "anti" aldols 7 or their silylethers 3. Hydroperoxide-assisted hydrolysis/esterification of products 7 yields enantiomerically pure methoxycarbonyl aldols (11, 12, 13, 14).