Chiral Phosphine Ligands of COAP and SKP Switched Regiodivergent Asymmetric Allylic Alkylation of MBH Adducts
Xing‐Yun Sun, Jiayu Song, Bailin Wang, Sheng‐Suo Zhou, Zhi‐Xiong Ou, Libo Li, Zheng Wang, Xing‐Wang Wang
Abstract
The palladium-catalyzed highly regioselective asymmetric allylic alkylation of 3′-indolyl-3-oxindole derivatives with Morita–Baylis–Hillman (MBH) carbonates was developed to facilely construct chiral 3,3′-bisindole derivatives under mild reaction conditions. The regioselectivity (α/γ) of MBH carbonates was efficiently switched in the presence of chiral oxalamide phosphine or spiroketal-based diphosphine/Pd(0) complexes as a chiral catalyst. A series of multifunctional 3,3′-bisindole derivatives with all-carbon quaternary stereogenic centers were obtained in high yields with good to excellent enantio-, diastereo-, and regioselectivity. The present process is endowed with some salient features such as broad substrate scope, N -protecting group-free, excellent stereoselectivity, as well as adjustable regioselectivity.