Iron-Catalyzed 1,4-Addition of α-Olefins to Dienes
作者:Benoît Moreau、Jessica Y. Wu、Tobias Ritter
DOI:10.1021/ol802524r
日期:2009.1.15
A new intermolecular, stereo- and regioselective iron-catalyzed 1,4-addition of α-olefins to 1,3-dienes using as low as 1 mol % of an iminopyridine−ferrous chloride complex was developed. Importantly, both double bonds of the linear 1,4-diene addition products are obtained with absolute stereocontrol.
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.