60.Reverse Regioselectivity in the Palladium(II) Thiourea Catalyzed Intermolecular Pauson–Khand Reaction
N. Wu, L. J. Deng, L. Z. Liu, Q. Liu, C. C. Li*, Z. Yang*
Which way? Palladium thiourea catalyzed Pauson–Khand reaction of norbornene with substituted alkynoates to afford selectively either α-carboxylated adducts or β-carboxylated adducts with the reverse regioselectivity has been demonstrated for the first time. Control of the regioselectivity in this transformation is governed by the addition of LiCl. A mechanistic interpretation to account for this observed regioselectivity is presented.
