A rhodium carbonyl complex, [RhCl(CO)(2)](2), serves as a catalyst of the intra- and inter-molecular Pauson-Khand reaction. By the use of the rhodium catalyst, cyclopentenone derivatives are prepared from various 1,6- and 1,7-enynes under 1 arm of CO. Furthermore, this rhodium-catalyzed reaction is accelerated by reducing partial pressure of CO to less than 1 atm. (C) 2001 Elsevier Science B.V. All rights reserved.
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
Diversity-oriented heterocyclic synthesis using divergent reactivity of N-substituted iso(thio)cyanates
作者:Jean-François Vincent-Rocan、Joshua S. Derasp、André M. Beauchemin
DOI:10.1039/c5cc07212c
日期:——
Carbon-substituted isocyanates and isothiocyanates are common building blocks in organic synthesis. In contrast, synthetic uses of N-substituted isocyanates and isothiocyanates are severely underdeveloped: few have been reported and their reactivity...
作者:Fuk Yee Kwong、Hang Wai Lee、Wai Har Lam、Liqin Qiu、Albert S.C. Chan
DOI:10.1016/j.tetasy.2006.03.036
日期:2006.4
An easily accessible chiral iridium-BINAP complex can effect the cooperative processes of decarbonylation of an aldehyde and cascaded enantioselective Pauson-Khand-type reaction. A survey of ligands revealed that atropisomeric aryl-diphosphine ligands were superior to chiral alkyl-diphosphines in this dual catalysis. Applying the reaction conditions of [IrCl(COD)](2)/(S)-BINAP complex with nonylaldehyde as a CO surrogate at 100 degrees C in anhydrous dioxane solvent, various 1,6-enynes were transformed to the corresponding optically active bicyclic cyclopentenones with excellent enantioselectivities (up to 98% ee). (c) 2006 Elsevier Ltd. All rights reserved.
Copper-Catalyzed Aerobic Intramolecular Carbo- and Amino-Oxygenation of Alkynes for Synthesis of Azaheterocycles
A synthetic method of highly substituted quinolines has been developed from N-(2-alkynylaryl)enamine carboxylates under Cu-catalyzed aerobic conditions via intramolecular carbo-oxygenation of alkynes. This strategy was further applied for N-alkynylamidines for amino-oxygenation of alkynes, leading to imidazole and quinazoline derivatives.