Highly Enantioselective Hydroformylation of Aryl Alkenes with Diazaphospholane Ligands
作者:Avery L. Watkins、Brian G. Hashiguchi、Clark R. Landis
DOI:10.1021/ol801723a
日期:2008.10.16
Asymmetric, rhodium-catalyzed hydroformylation of terminal and internal aryl alkenes with diazaphospholane ligands is reported. Under partially optimized reaction conditions, high enantioselectivity (>90% ee) and regioselectivities (up to 65:1 alpha:beta) are obtained for most substrates. For terminal alkenes, both enantioselectivity and regioselectivity are proportional to the carbon monoxide partial
Enantioselective hydroformylation of 2- and 4-substituted styrenes with PtCl2[(R)-BINAP] + SnCl2 ‘in situ’ catalyst
作者:Péter Pongrácz、László Kollár
DOI:10.1016/j.jorganchem.2016.10.013
日期:2016.12
hydroformylation of 2-substituted styrenes: the presence of substituents characterised by larger steric parameter resulted in the highly favoured formation of the linear aldehyde. For instance, regioselectivities of 45%, 22% and 7% towards branched aldehyde were obtained with styrene, 2-fluoro- and 2-bromostyrene, respectively, at 80 °C reaction temperature. In addition to the characteristic change of regioselectivity
We report herein on an accessible protocol for the asymmetric hydroformylation of vinylarenes usingformaldehyde as a substitute for syngas. The regioselectivity (branched/linear = up to 96/4) and enantioselectivity (up to 95% ee) can be attributed to the use of chiral Ph-bpe as a ligand.
Influence of the 4-Substituents on the Reversal of Enantioselectivity in the Asymmetric Hydroformylation of 4-Substituted Styrenes with PtCl(SnCl<sub>3</sub>)[(2<i>S,</i>4<i>S</i>)-BDPP]
The enantioselectivity of the asymmetric hydroformylation of 4-substituted styrenes in the presence of an in situ catalyst, formed from PtCl(SnCl3)[(2S,4S)-BDPP] and tin(II) chloride, was influenced by the reaction temperature. The preferred formation of the S and the R enantiomers of the branched aldehyde regioisomers (2a–g) was observed at low and high temperatures, respectively. The electron-donor
作者:Garhwal, Subhash、Dong, Yuyang、Mai, Binh Khanh、Liu, Peng、Buchwald, Stephen L.
DOI:10.1021/jacs.4c04287
日期:——
hydride (CuH) catalysis is reported. Key to the success of the method was the use of the mild Lewis acid zinc triflate to promote the formation of oxocarbenium electrophiles through the activation of diethoxymethyl acetate. Using the newly developed protocol, a broad range of vinyl arene substrates underwent efficient hydroacetalization reactions to provide access to highly enantioenriched α-aryl acetal