Formate as a CO surrogate for cascade processes: Rh-catalyzed cooperative decarbonylation and asymmetric Pauson–Khand-type cyclization reactions
作者:Hang Wai Lee、Albert S. C. Chan、Fuk Yee Kwong
DOI:10.1039/b702718d
日期:——
A rhodium-(S)-xyl-BINAP complex-catalyzed tandem formate decarbonylation and [2 + 2 + 1] carbonylative cyclization is described; this cooperative process utilizes formate as a condensed CO source, and the newly developed cascade protocol can be extended to its enantioselective version, providing up to 94% ee of the cyclopentenone adducts.
作者:Fuk Yee Kwong、Yue Ming Li、Wai Har Lam、Liqin Qiu、Hang Wai Lee、Chi Hung Yeung、Kin Shing Chan、Albert S. C. Chan
DOI:10.1002/chem.200401237
日期:2005.6.20
operationally simple protocol allows both catalyst and reactants to be handled under air without precautions. Various enynes were transformed to the corresponding bicycliccyclopentenones in good yield and enantiomeric excess (up to 95 % ee). A study of the electronic effects of the enyne substrates revealed a correlation between the electronic properties of the substrates and the ee value obtained in
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
Co/Rhheterobimetallic nanoparticles were prepared from cobalt-rhodium carbonyl clusters [Co2Rh2(CO)12 and Co3Rh(CO)12] and immobilized on charcoal. HR-TEM revealed that the size of the heterobimetallic nanoparticles was ca. 2 nm and ICP-AES analysis showed a 2 : 2 and a 3 : 1 cobalt-rhodium stoichiometry (Co2Rh2 and Co3Rh1) in the heterobimetallic nanoparticles. The Co/Rhheterobimetallic nanoparticles
An Intramolecular Titanium-Catalyzed Asymmetric Pauson−Khand Type Reaction<sup>1</sup>
作者:Frederick A. Hicks、Stephen L. Buchwald
DOI:10.1021/ja990683m
日期:1999.8.1
The development of the first catalytic asymmetric Pauson−Khandtype cyclization of enynes is described. The active catalyst, (S,S)-(EBTHI)Ti(CO)2 (1), is generated in situ from (S,S)-(EBTHI)TiMe2 (2). A variety of 1,6-enynes can be converted to the corresponding cyclopentenones in high yield (70−94%) with excellent ee's (87−96%). Limitations of the catalyst with respect to substrate structure are discussed