Highly stereoselective addition of Grignard reagents to C-cyclopropylnitrone via the bisected s-trans conformation. An efficient synthesis of PEDC, a potent NMDA receptor antagonist having a cyclopropane structure

An efficient synthesis of PEDC (1), a potent NMDA receptor antagonist of a cyclopropane structure, was achieved. The highly stereoselective addition reaction of MeMgBr to C-cyclopropylnitrone 2, via its bisected s-trans conformation which can be predicted from the stereo-electronic effects, was developed as the key step. The s-trans conformation predominant in C-cyclopropynitrone 2 was suggested by NOE experiments.