Chiral Monodentate Trialkylphosphines Based on the Phospholane Architecture
作者:Pavel A. Donets、Tanguy Saget、Nicolai Cramer
DOI:10.1021/om3008772
日期:2012.12.10
tricyclohexylphosphine and tri-tert-butylphosphine in catalytic asymmetric transformations. We present a convenient and modularsynthesis of a set of chiral monodentate ligands with different steric demands based on the popular phospholane scaffold. Their steric and electronic properties were determined by their corresponding nickel and palladium complexes. They represent good mimics of the popular
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
Chiral Monodentate Phosphines and Bulky Carboxylic Acids: Cooperative Effects in Palladium-Catalyzed Enantioselective C(sp3)-H Functionalization
作者:Tanguy Saget、Sébastien J. Lemouzy、Nicolai Cramer
DOI:10.1002/anie.201108511
日期:2012.2.27
important indoline scaffold is provided with enantiomeric ratios of up to 98:2 in palladium(0)‐catalyzed C(sp3)–H activations of aryl triflates. The key is the combination of the electron‐rich monodentate Sagephos and the bulky 9H‐xanthene‐9‐carboxylicacid. Both participate in a highly cooperative manner in the enantiodetermining concerted‐deprotonation‐metalation step (see scheme, Tf=triflate).