Cobalt-Catalyzed Thiolative Lactonization of Alkynes with Double CO Incorporation
摘要:
When the Co-2(CO)(8)-catalyzed reaction of alkynes with thiols is conducted under the pressure of carbon monoxide, a novel thiolative lactonization with simultaneous introduction of two carbon monoxide molecules into the carbon carbon triple bonds takes place successfully to afford alpha,beta-unsaturated gamma-thio-gamma-lactones with excellent regioselectivity.
A correction to the interpretation of the CO stretching region of the infrared spectra of Co2(CO)6(HC2R) complexes with terminal acetylenes as bridging ligands and an IR indication for the distorted molecular geometry of Co2(CO)6(C6H5C2C6H5 in solution
Carbamate as an accelerating group in intermolecular Pauson-Khand reaction
作者:Shota Asano、Kaori Itto-Nakama、Hirokazu Arimoto
DOI:10.1016/j.tetlet.2020.151974
日期:2020.6
The Pauson-Khandreaction (PKR) is a powerful means for the construction of cyclopentenones. However, its applications have been limited to the intramolecular version of this reaction because poor yield and regioselectivity are often the major problems in intermolecular PKR. Here we describe that a carbamate moiety in alkene substrate accelerates this intermolecular PKR. The reaction of N-4-dimethylaminophenyl
Carbonylative Cyclization of Alkynes Using Cobalt Carbonyl Species Prepared via Reduction of CoBr<sub>2</sub> with Zn under a Carbon Monoxide Atmosphere
作者:Thotapally Rajesh、Mariappan Periasamy
DOI:10.1021/om990534c
日期:1999.12.1
Alkyne-Co-2(CO)(6) complexes prepared in situ using CoBr2, Zn, and CO give the corresponding cyclopentenones or cyclopentadienones on heating in toluene or in CH2Cl2 at 25 degrees C in the presence of DMSO or amines.