Geometry-Constrained Iminopyridyl Palladium-Catalyzed Hydroarylation of Alkynes to Prepare Tri-substituted Alkenes Using Alcohol as Reductant
作者:Ke Wu、Nan Sun、Baoxiang Hu、Zhenlu Shen、Liqun Jin、Xinquan Hu
DOI:10.1002/adsc.201800423
日期:2018.8.17
straightforward method to prepare tri‐substituted alkenes through palladium‐catalyzed hydroarylation of alkynes with aryl bromides. Diarylacetylenes and alkyl(aryl)acetylenes could be well hydroarylated with various aryl bromides in moderate to excellent yields. Mechanistic studies suggested that alcohol was the reductant to provide hydride through β‐H elimination. Gram scale reaction further demonstrated
Mizoroki–Heck reaction of 1,2-disubstituted aryl alkenes: Variables of synthesis, solvent and ligand modulation of reactivity
作者:Pronnoy G. Bangar、Priyanka R. Jawalkar、Swapnil R. Dumbre、Pallavi K. Raut、Dharmaraj J. Patil、Neethu Tv、Shana Sudhakaran、Suresh Iyer
DOI:10.1080/00397911.2020.1811986
日期:2020.12.16
Abstract Reaction of aryl iodides with 1,2-disubstituted aryl alkenes in the presence of TBABr/TBACl gave high yields of the Mizoroki–Heck product. Phosphine ligands were used for the modulation of reactivity and stereoselectivity, for the reaction of 4-iodoanisole with cinnamaldehyde. tert-Bu3P.HBF4 gave the highest E:Z ratio of 1:0.08. The use of PEG-200 and PEG-400 as solvent could activate the
We present an approach to utilize water as the hydride source via Pd(II)/Pd(0) catalysis. As a case study, we have achieved a diboron mediated Pd(II)-catalyzed hydroarylation of alkynes using arylboronic acids. This approach not only complements conventional reactivity of Pd via Pd(0)/Pd(II) cycle for the hydroarylation but also utilizes water as the hydride source. We believe this would particularly
and dioxygen serve as oxidants in highly stereoselective oxidative Pd‐catalyzed Heck arylations in which aryl boronicacids are used to synthesize triarylalkyl‐substituted olefins. The reactions occur under very mild conditions at room temperature. As an example, the threefold sequential arylation of methyl acrylate is the crucial step in the stereoselective synthesis of Z‐Tamoxifen.