Preparation of β-Lactams by Mannich-Type Addition of Ethyl(trimethyl­silyl)acetate (ETSA) to N-(2-Hydroxyphenyl)aldimine Sodium Salts

Abstract : The synthesis of highly substituted β-lactams was achieved by addition of air-stable ethyl(trimethylsilyl)acetate derivatives to N-(2-hydroxyphenyl)aldimine sodium salts in a THF-EtCN mixture. This reaction proceeds with moderate to good yields and diastereomeric ratio of up to 78:22. The reactivity of the N-(2-hydroxyphenyl)aldimine can be modified by simply changing the co-solvent from EtCN to MeCN to afford the cyanomethylated addition product.