Mechanistic insights into catalytic linear cross-dimerization between conjugated dienes and styrenes by a ruthenium(0) complex
摘要:
The mechanistic studies for linear cross-dimerization between 2,3-dimethylbuta-1,3-diene and styrene by a Ru(0) complex, Ru(eta(6)-naphthalene)(eta(4)-1,5-COD) (1), are performed both by kinetic and computational studies. This reaction is basically zero-order to both of the diene and styrene concentrations and first-order to the catalyst concentration. The Hammett plot using p-substituted styrenes gives a linear relationship with a positive slope (rho = +0.482). The deuterium isotope experiment clearly shows the present reaction being a formal 1,4-addition of a C-H bond in styrene to cisoid-1,3-diene. These kinetic studies show the reaction proceeding via oxidative coupling mechanism that is also supported by the DFT calculations. (C) 2015 Elsevier B.V. All rights reserved.
Direct Cross-Coupling of Allylic C(sp<sup>3</sup>
)−H Bonds with Aryl- and Vinylbromides by Combined Nickel and Visible-Light Catalysis
作者:Long Huang、Magnus Rueping
DOI:10.1002/anie.201805118
日期:2018.8.6
An efficient protocol for the direct allylic C(sp3)−Hbond activation of unactivated tri‐ and tetrasubstituted alkenes and their functionalization with aryl‐ and vinylbromides by nickel and visible‐light photocatalysis has been developed. The method allows C(sp2)−C(sp3) formation under mild reaction conditions with good functional‐group tolerance and excellent regioselectivity.