Enantioselective N-Heterocyclic Carbene Catalyzed Synthesis of Functionalized Indenes
作者:Changhe Zhang、David W. Lupton
DOI:10.1021/acs.orglett.7b01981
日期:2017.9.1
An enantioselective NHC (N-heterocycliccarbene) catalyzed synthesis of indenes from bifunctional α,β-unsaturated acyl fluorides and TMS enol ethers has been discovered. The reaction has broad generality (31 examples) and proceeds with high levels of enantioselectivity (most >92:8 er). Mechanistically the reaction likely occurs via a Michael/β-lactonization/decarboxylation sequence. Derivatization
Divergent Iron-Catalyzed Coupling of<i>O</i>-Acyloximes with Silyl Enol Ethers
作者:Hai-Bin Yang、Nicklas Selander
DOI:10.1002/chem.201605636
日期:2017.2.3
An iron‐catalyzedcoupling reaction of O‐acyloximes and O‐benzoyl amidoximes with silyl enol ethers is reported. The protocol provides access to functionalized pyrroles, 1,6‐ketonitriles, pyrrolines and imidazolines via carbon‐centered radicals generated from an initially formed iminyl radical. The intramolecular cyclization and ring‐opening processes of the iminyl radical take place preferentially
Synthesis of 3-Fluoropyridines via Photoredox-Mediated Coupling of α,α-Difluoro-β-iodoketones with Silyl Enol Ethers
作者:Sofya I. Scherbinina、Oleg V. Fedorov、Vitalij V. Levin、Vladimir A. Kokorekin、Marina I. Struchkova、Alexander D. Dilman
DOI:10.1021/acs.joc.7b02467
日期:2017.12.15
A method for the synthesis of diversely substituted 3-fluoropyridines from two ketone components is described. The reaction involves photoredox coupling of α,α-difluoro-β-iodoketones with silyl enol etherscatalyzed by fac-Ir(ppy)3 under blue LED irradiation with subsequent one-pot condensation with ammonium acetate. Based on cyclic voltammetry studies, it was determined that α,α-difluoro-β-iodoketones
three-component coupling of acyl fluorides, silyl enol ethers, and alkynoates. The key to the success of the reaction is the formal transmetalation between pentacoordinate P(V) species (i.e., fluorophosphorane) and a silyl enol ether, which allows for C–C bond formation between the polarity-mismatched sites. The bond formation that cannot be attained even by transition metal catalysis is accomplished
Aryl Pyrazoles from Photocatalytic Cycloadditions of Arenediazonium
作者:Luana Cardinale、Michael Neumeier、Michal Majek、Axel Jacobi von Wangelin
DOI:10.1021/acs.orglett.0c02514
日期:2020.9.18
conditions (rt, 20 min) with catalytic [Ru(bpy)3]2+ under blue-light irradiation and exhibited compatibility with several functional groups (e.g., I, SF5, SO2NH2, N3, CN) and perfect levels of regiocontrol. Mechanistic studies (luminescence spectroscopy, CV, DFT, radical trapping, quantum yield determination) documented an initial oxidative quenching of the excited photocatalyst and the operation of