Catalytic Asymmetric Enyne Addition to Aldehydes and Rh(I)-Catalyzed Stereoselective Domino Pauson–Khand/[4 + 2] Cycloaddition
作者:Wei Chen、Jia-Hui Tay、Jun Ying、Xiao-Qi Yu、Lin Pu
DOI:10.1021/jo3026065
日期:2013.3.15
propargylic alcohols prepared from the catalyticasymmetric enyne addition to aliphatic aldehydes are used to prepare a series of opticallyactive trienynes. In the presence of a catalytic amount of [RhCl(CO)2]2 and 1 atm of CO, the opticallyactive trienynes undergo highly stereoselective domino Pauson–Khand/[4 + 2] cycloaddition to generate opticallyactive multicyclic products. The Rh(I) catalyst
Asymmetric transfer hydrogenation of unsaturated ketones; factors influencing 1,4- vs 1,2- regio- and enantioselectivity, and alkene vs alkyne directing effects
作者:Thomas H. Hall、Hannah Adams、Vijyesh K. Vyas、K.L. Michael Chu、Martin Wills
DOI:10.1016/j.tet.2020.131771
日期:2021.1
A detailed study has been completed on the asymmetric transferhydrogenation (ATH) of a series of enones using Ru(II) catalysts. Electron-rich rings adjacent to the CO group reduce the level of CO reduction compared to CC. The ATH reaction can readily discriminate between double and triple bonds adjacent to ketones, reducing the double bond but leaving a triple bond intact in the major product.
Rhodium-Catalyzed Intra- and Intermolecular [5 + 2] Cycloaddition of 3-Acyloxy-1,4-enyne and Alkyne with Concomitant 1,2-Acyloxy Migration
作者:Xing-Zhong Shu、Xiaoxun Li、Dongxu Shu、Suyu Huang、Casi M. Schienebeck、Xin Zhou、Patrick J. Robichaux、Weiping Tang
DOI:10.1021/ja2109097
日期:2012.3.21
type of rhodium-catalyzed [5 + 2] cycloaddition was developed for the synthesis of seven-membered rings with diverse functionalities. The ring formation was accompanied by a 1,2-acyloxy migration event. The five- and two-carbon components of the cycloaddition are 3-acyloxy-1,4-enynes (ACEs) and alkynes, respectively. Cationic rhodium(I) catalysts worked most efficiently for the intramolecular cycloaddition
Metal-free synthesis of activated ynesulfonamides and tertiary enesulfonamides
作者:Lucile Andna、Laurence Miesch
DOI:10.1039/c9ob00947g
日期:——
An operationally simple synthesis of activated ynesulfonamides and enesulfonamides is described. Ynesulfonamides can be obtained through reaction of sulfonylamides with activated bromoalkynes and Triton B in a short time at room temperature. Likewise, terminal alkynes react with sulfonylamides to provide enesulfonamides. Z/E enesulfonamides can be transformed exclusively into E enesulfonamides.
A wide variety of 1,4-diynes have been constructed via a novel FeCl3-catalyzed coupling reaction of propargylic alcohols with alkynylsilanes. This synthetic approach provides a general, efficient, ...