Enantioselective synthesis of 2-methyl indolines by palladium catalysed asymmetric C(sp3)–H activation/cyclisation
作者:Saithalavi Anas、Alex Cordi、Henri B. Kagan
DOI:10.1039/c1cc14292e
日期:——
activation by an intramolecular ArPdX species and subsequent cyclisation was developed. Palladium catalysts using commercially available chiral diphosphines yield good ee's (up to 93% ee) in the synthesis of 2-methyl indolines from 2-halo N-isopropyl anilides. This approach was also employed for the synthesis of enantioenriched cyclohexyl fused indolines with moderate enantioselectivities.
The first efficient palladium(0)-catalyzed enantioselective C(sp3)–H activation reaction using a catalytic chiral base and an achiral phosphine ligand is reported. Fine-tuning the binol-derived phosphoric acid pre-catalyst and the reaction conditions was found to be crucial to achieve high levels of enantioselectivity for a variety of indoline products containing both tri- and tetrasubstituted stereocenters