Microwave‐Assisted Rhodium‐Complex‐Catalyzed Cascade Decarbonylation and Asymmetric Pauson–Khand‐Type Cyclizations
作者:Hang Wai Lee、Lai Na Lee、Albert S. C. Chan、Fuk Yee Kwong
DOI:10.1002/ejoc.200800272
日期:2008.7
Microwave-assisted Rh–diphosphane-complex-catalyzed dual catalysis is reported. This cooperative process provides [2+2+1] cycloadducts by sequential decarbonylation of aldehyde or formate and carbonylation of enynes within a short period of time. Various O-, N-, and C-tethered enynes were transformed into the corresponding products in good yields. The first enantioselective version of this microwave-accelerated
Atom-Economical Ni-Catalyzed Diborylative Cyclization of Enynes: Preparation of Unsymmetrical Diboronates
作者:Natalia Cabrera-Lobera、M. Teresa Quirós、William W. Brennessel、Michael L. Neidig、Elena Buñuel、Diego J. Cárdenas
DOI:10.1021/acs.orglett.9b02485
日期:2019.8.16
We report a Ni-catalyzed diborylative cyclization of enynes that affords carbo- and heterocycles containing both alkyl- and alkenylboronates. The reaction is fully atom-economical, shows a broad scope, and employs a powerful and inexpensive catalytic Ni-based system. The reaction mechanism seems to involve activation of the enyne by Ni(0) through oxidative cyclometalation of the enyne prior to diboron
Cobalt-Catalyzed Asymmetric Hydroboration/Cyclization of 1,6-Enynes with Pinacolborane
作者:Songjie Yu、Caizhi Wu、Shaozhong Ge
DOI:10.1021/jacs.7b01708
日期:2017.5.17
We report a cobalt-catalyzed asymmetric hydroboration/cyclization of 1,6-enynes with catalysts generated from Co(acac)2 and chiral bisphosphine ligands and activated in situ by reaction with pinacolborane (HBpin). A variety of oxygen-, nitrogen-, and carbon-tethered 1,6-enynes underwent this asymmetric transformation, yielding both alkyl- and vinyl-substituted boronate esters containing chiral tetrahydrofuran
A highly chemo- and stereoselective cobalt-catalyzed hydroarylative cyclization of 1,6-enynes with aromaticketones and esters to synthesize functionalized pyrrolidines and dihydrofurans is described. A mechanism involving cobaltacycle triggered C–H activation of aromaticketones and esters was proposed.
Rh-Catalyzed Aqueous Pauson-Khand-Type Cycloaddition in Microwave-Irradiated Medium
作者:Fuk Kwong、Albert Chan、Hang Lee
DOI:10.1055/s-2008-1078413
日期:2008.6
Microwave-assisted Rh-catalyzed dual catalysis in aqueous medium is described. This tandem process transforms the enyne to cycloadduct by cascade decarbonylation of formate ester and subsequently carbonylation of enyne under microwave-irradiated conditions.