Enantioselective Synthesis of 3-Allylindoles from Indolin-2-imines and MBH Carbonates via Nucleophilic Catalysis

With chiral amine (DHQD)2PHAL as nucleophilic catalyst, asymmetric synthesis of enantioenriched 3-allylindoles was achieved from indolone-2-imines and MBH carbonates. Compared with our previous chiral phosphine catalysis, the chiral amine had exactly the opposite effect in terms of enantioselectivity. Importantly, we could obtain each enantiomer by adjusting the catalyst system. A chiral amine (DHQD)2PHAL catalyzed 3-allylation of indolin-2-imines and MBH carbonates has been established, affording enantioenriched 3-allylindoles in high yields. Importantly, based on our previous work, we were able to obtain each enantiomer of chiral 3-allylindoles by fine-tuning the catalytic system. image