Noncovalent Interactions in the Oxazaborolidine-Catalyzed Enantioselective Mukaiyama Aldol

Current models for oxazaborolidine-catalyzed transition-state structures are determined by C-H center dot center dot center dot O-B and C-H center dot center dot center dot O=S formyl hydrogen bonding between the electrophile and catalyst. However, selectivity in the oxazaborolidine-catalyzed Mukaiyama aldol cannot be fully rationalized using these models. Combined density functional theory and noncovalent interaction analyses reveal a new reaction model relying on C-H center dot center dot center dot O, C-H center dot center dot center dot pi, and pi-pi interactions between the nucleophile, electrophile, and catalyst to induce selectivity.

Automated summary

A new reaction model relying on different interactions between the nucleophile, electrophile, and catalyst has been proposed to explain the selectivity in the oxazaborolidine-catalyzed Mukaiyama aldol reaction, as the current models based on hydrogen bonding alone are insufficient.