Stereoselective Catalytic Direct Additions of Sulfonylimidates

Key words

sulfonylimidates - direct addition - 1,8-diazabicyclo[5.4.0]undec-7-ene

Significance

The authors describe the first examples of a highly stereoselective catalytic direct addition reaction of sulfonylimidates with Mannich-type, Michael-type, and azodicarboxylate acceptors. High anti-selectivity is observed for a large scope of substrates. The synthetic utility of the product is demonstrated through a variety of post-reaction modifications. An example of the direct formation of an α-amino acid derivative is also shown.

Comment

This report highlights a tertiary amine catalyzed direct addition of α-alkyl-substituted ester equivalents, and demonstrates the novel use of sulfonylimidates in a catalytic direct addition reaction. Metals are known to catalyze reactions of α-alkyl-substituted carbonyl compounds, though these methodologies are largely limited to carbonyls with electron-withdrawing α-substituents: For examples, see: H. Morimoto et al. Angew. Chem. Int. Ed. 2006, 45, 3146 and S. Saito, T. Tsubogo, S. Kobayashi. Chem. Commun. 2007, 1236.