Gold(I)-Catalyzed Enantioselective Intramolecular Dehydrative Amination of Allylic Alcohols with Carbamates
作者:Paramita Mukherjee、Ross A. Widenhoefer
DOI:10.1002/anie.201107877
日期:2012.2.6
Aliphatic nitrogen heterocycles—either five‐ or six‐membered—are formed in high yield and with up to 94 % ee when a 1:2 mixture of [(S)‐2](AuCl)2 and AgClO4 is used as the catalyst for the title reaction.
Enantioselective Intramolecular Allylic Substitution via Synergistic Palladium/Chiral Phosphoric Acid Catalysis: Insight into Stereoinduction through Statistical Modeling
作者:Cheng‐Che Tsai、Christopher Sandford、Tao Wu、Buyun Chen、Matthew S. Sigman、F. Dean Toste
DOI:10.1002/anie.202006237
日期:2020.8.17
The mode of asymmetric induction in an enantioselective intramolecular allylic substitution reaction catalyzed by a combination of palladium and a chiral phosphoric acid was investigated by a combined experimental and statistical modeling approach. Experiments to probe nonlinear effects, the reactivity of deuterium‐labeled substrates, and control experiments revealed that nucleophilic attack to the
The intramolecular gold-catalyzed asymmetric hydroamination of allenes was studied by screening a series of mononuclear gold(I) and -(III) complexes in combination with silver salts. Among the various chiral monophosphine and diaminocarbene ligands tried, the best catalysts arose from mononuclear gold(I) complexes synthesized from BINOL-based phosphoramidite ligands. The latest were improved by addition of bulky substituents at specific positions of the BINOL scaffold. The resulting gold(I) complexes were combined with selected silver salts to afford efficient catalysts for intramolecular hydroamination of allenes at room temperature or below, with good conversions and enantioselectivities.
Silver-Catalysed Enantioselective Addition of OH and NH Bonds to Allenes: A New Model for Stereoselectivity Based on Noncovalent Interactions
作者:Jannine L. Arbour、Henry S. Rzepa、Julia Contreras-García、Luis A. Adrio、Elena M. Barreiro、King Kuok Mimi Hii
DOI:10.1002/chem.201200547
日期:2012.9.3
complexes to catalyse the enantioselective addition of OH and NHbonds to allenes is demonstrated for the first time by using optically active anionic ligands that were derived from oxophosphorus(V) acids as the sources of chirality. The intramolecular addition of acids, alcohols, and amines to allenes can be achieved with up to 73 % ee. The exploitation of a CH anomeric effect allowed the absolute configuration