title: Spiroketal-based diphosphine ligands in Pd-catalyzed asymmetric allylic amination of Morita-Baylis-Hillman adducts: exceptionally high efficiency and new mechanism.
abstract: Exceptionally high activity (with a TON up to 4750) of the palladium complexes of SKP ligand was discovered in the catalysis of asymmetric allylic amination of MBH adducts with aromatic amines. A comprehensive mechanistic study indicates that the unique structural features of the SKP ligand, with a long P···P distance in its solid-state structure, were favorable for allowing two P atoms to play a bifunctional role in the catalysis. Herein, one of the P atom forms a C-P σ-bond with the terminal carbon atom of allyl moiety as a Lewis base, and an alternative P atom coordinates to Pd atom. The cooperative action of organo- and organometallic catalysis discovered in the present catalytic system is most likely responsible for its high activity, as well as excellent regio- and enantioselectivities. The mechanism disclosed in the present catalytic system is distinct from most of the currently recognized mechanisms for Pd-catalyzed allylic substitutions.
authors: State Key Laboratory of Oganometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, People's Republic of China.
authors: Xiaoming
authors: X
authors: Wang
authors: Peihua
authors: P
authors: Guo
authors: Zhaobin
authors: Z
authors: Han
authors: Xubin
authors: X
authors: Wang
authors: Zheng
authors: Z
authors: Wang
authors: Kuiling
authors: K
authors: Ding