Asymmetric Titanium-Catalyzed Cyclopropanation of Nitriles with Grignard Reagents

Abstract

Abstract The titanium-catalyzed asymmetric cyclopropanation of cyanoesters­ with Grignard reagents was investigated for the first time. Particularly, the study of the efficiency of Taddol-based titanium complexes­ has shown that the prior preparation of Taddol titanium complexes was not required and a large panel of ligands was evaluated by using this approach. The spirocyclopropanelactams were obtained with good diastereoselectivity and with moderate enantioselectivities from the main diastereoisomer (up to 32%).

Keywords

• cyclopropanes
• enantioselectivity
• grignard reagents
• nitriles­
• spiro compounds
• titanium