Synthesis of Allylboranes via Cu(I)-Catalyzed B–H Insertion of Vinyldiazoacetates into Phosphine–Borane Adducts
作者:Denis Drikermann、Robert S. Mößel、Walid K. Al-Jammal、Ivan Vilotijevic
DOI:10.1021/acs.orglett.9b04619
日期:2020.2.7
Cu(I) catalysts enable C-B bond formation via direct insertion of vinyldiazoacetates into B-H bonds of borane-phosphine Lewis adducts to form phosphine-protected allylboranes under mild conditions. The resulting allylborane-phosphine Lewis adducts can be used in the diastereoselective allylation of aldehydes directly without the need for removal of the phosphine. The allylation reaction proceeds with
Access to N-Substituted 2-Pyridones by Catalytic Intermolecular Dearomatization and 1,4-Acyl Transfer
作者:Guangyang Xu、Ping Chen、Pei Liu、Shengbiao Tang、Xinhao Zhang、Jiangtao Sun
DOI:10.1002/anie.201812937
日期:2019.2.11
A novel rhodium‐catalyzed dearomatization of O‐substituted pyridines to access N‐substituted 2‐pyridones has been developed. A computational study suggests a mechanism involving the formation of a pyridinium ylide followed by an unprecedented 1,4‐acyl migratory rearrangement from O to C. Furthermore, the chiral dirhodium complexes serve as the catalyst for the asymmetric transformation with excellent
Borane Catalyzed Selective Diazo Cross‐Coupling Towards Pyrazoles
作者:Ayan Dasgupta、Sanjukta Pahar、Rasool Babaahmadi、Lukas Gierlichs、Brian F. Yates、Alireza Ariafard、Rebecca L. Melen
DOI:10.1002/adsc.202101312
日期:2022.2.15
Decomposition of donor-acceptor diazocompounds leads to the formation of reactive carbene intermediates. These can undergo a wide variety of carbene transfer reactions to yield synthetically useful products. Herein, we report a selective borane catalyzed cyclization reaction from the combination of two different diazocompounds to afford N-substituted pyrazoles. The selective decomposition of the
Tris(pentafluorophenyl)borane‐Catalyzed Carbenium Ion Generation and Autocatalytic Pyrazole Synthesis—A Computational and Experimental Study
作者:Ayan Dasgupta、Rasool Babaahmadi、Sanjukta Pahar、Katarina Stefkova、Lukas Gierlichs、Brian F. Yates、Alireza Ariafard、Rebecca L. Melen
DOI:10.1002/anie.202109744
日期:2021.11.8
diazoacetates and aryl esters afforded highly regioselective N-alkylated pyrazoles. These reactions involve an autocatalytic process in which in situ formed carbenium species act as a catalyst to regioselectively afford pyrazoles. Detailed DFT studies were carried out to explain the reaction mechanism.
Enantioselective insertion of vinyl diazoacetates into O–H bonds of carboxylic acids
作者:Jiawei Chen、Ying Shao、Shengbiao Tang、Jiangtao Sun
DOI:10.1039/d4nj00289j
日期:——
A highly regio- and enantioselective insertion of vinyl diazoacetates into O–H bonds of carboxylicacids has been realized by cooperative catalysis of an achiral rhodium complex and a chiral phosphoric acid. The insertion reaction exhibits highly carbenic reactivity rather than vinylogous reactivity, representing a rare example towards α-acyloxyl-β,γ-unsaturated esters, and the corresponding esters