Scope of the Intramolecular Titanocene-Catalyzed Pauson−Khand Type Reaction<sup>1</sup>
作者:Frederick A. Hicks、Natasha M. Kablaoui、Stephen L. Buchwald
DOI:10.1021/ja990682u
日期:1999.6.1
A Pauson−Khandtype conversion of enynes to bicycliccyclopentenones employing the commercially available precatalyst titanocene dicarbonyl is described. This methodology shows excellent functional group tolerance for a group 4 metallocene-catalyzed process. The scope and limitations of this cyclization with respect to 1,6-, 1,7- and 1,8-enynes with a variety of terminal alkyne substituents, chiral
Direct synthesis of alkynes from inexpensive, abundant alcohols was achieved in high yields (greater than 40 examples, up to 95% yield) through a SO2F2-promoted dehydration and dehydrogenation process. This straightforward transformation of sp3-sp3 (C-C) bonds to sp-sp (C≡C) bonds requires only inexpensive and readily available reagents (no transition metals) under mild conditions. The crude alkynes
Rhodium(I)-Catalyzed Ring-Closing Reaction of Allene-Alkene-Alkynes: One-Step Construction of Tricyclo[6.4.0.0<sup>2,6</sup>
] and Bicyclo[6.3.0] Skeletons from Linear Carbon Chains
afforded bicyclo[6.3.0]undecatriene derivatives instead of tricyclic compounds, the latter of which are well known as a basic skeleton of naturally occurring octanoids. On the basis of two experiments with deuterated substrates, a plausible reaction mechanism for the construction of these products was proposed.
Copper-Catalyzed Carbamoylation of Terminal Alkynes with Formamides via Cross-Dehydrogenative Coupling
作者:Jin-Ji Wu、Yinwu Li、Hai-Yun Zhou、A-Hao Wen、Chu-Chu Lun、Su-Yang Yao、Zhuofeng Ke、Bao-Hui Ye
DOI:10.1021/acscatal.5b02881
日期:2016.2.5
efficient approach for direct carbamoylation of terminal alkynes with formamides affording propiolamides has been developed by copper-catalyzed oxidative cross coupling of C(sp)-H and C(sp2)-H bonds in the presence of a pincer ligand with two imidazolyl groups. The catalytic reaction is compatible with diverse functional groups but sensitive to the electronic effect of terminal alkyne and the steric effect
The highly enantioselective alkynylation of isatins, catalyzed by a bifunctional guanidine/CuI catalyst under mild reaction conditions, is described. The reaction is broad in scope with respect to alkyl/aryl‐substituted terminal alkynes and substituted isatins, thus affording bioactive propargylic alcohols in excellent yields and enantioselectivities.