A new type of carbonylation of styrenes was achieved under a 1:1 mixture of CO (0.5 atm) and O2 (0.5 atm) in the presence of Pd(OAc)2 combined with H5PMo10V2O40·nH2O to give 4-methyl-2-phenylnaphthalen-1(4H)-one in 78% yield. Various substituted styrenes were also carbonylated to the corresponding substituted arylnaphthalen-1(4H)-ones in moderate yields. The reaction was found to proceed in two stages involving the head-to-tail dimerization of styrenes, followed by carbonylation of the resulting dimers. Styrenes were efficiently dimerized under air (1 atm) in the absence of CO even at room temperature to produce head-to-tail dimers in good yields.
serve as a cooperative reductant to transform ketones via carbocations that undergo β-H elimination much faster than hydride transfer from silane to produce alkenes with high selectivity. Alternatively, the presence of indoles would incept the protonated ketones to generate carbocations, allowing access to Csp2–Csp3 bondformation with high reactivity and selectivity in “one pot”.
Chemoselective hydroamination of vinyl arenes catalyzed by an NHC-amidate-alkoxide Pd(II) complex and p-TsOH
作者:Richard Giles、Justin O’Neill、Joo Ho Lee、Michael K. Chiu、Kyung Woon Jung
DOI:10.1016/j.tetlet.2013.05.101
日期:2013.7
The hydroamination of various substituted vinyl arenes with benzenesulfonamide was explored using an NHC-amidate-alkoxide palladium catalyst in conjunction with p-TsOH. Utilizing halide-substituted and electron-rich vinyl arenes, this methodology selectively furnished the cross-coupled hydroamination products in moderate to excellent yields in a Markovnikov fashion while greatly reducing undesired acid-catalyzed homocoupling of the vinyl arenes. Electron-rich vinyl arenes typically required milder conditions than electron-poor ones. While most effective for para-substituted substrates, the catalyst system also furnished the desired products from ortho- and meta-substituted vinyl arenes with high chemoselectivities. (C) 2013 Elsevier Ltd. All rights reserved.
Transition-Metal-Free Sulfuration/Annulation of Alkenes: Economical Access to Thiophenes Enabled by the Cleavage of Multiple C–H Bonds
作者:Liang Chen、Hao Min、Weilan Zeng、Xiaoming Zhu、Yun Liang、Guobo Deng、Yuan Yang
DOI:10.1021/acs.orglett.8b03078
日期:2018.12.7
and transition-metal-free strategy for the synthesis of thiophenes from substituted buta-1-enes with potassium sulfide has been presented. The reaction achieves double C–Sbondformations via cleavage of multiple C–H bonds and provides an efficientapproach to access various functionalized thiophenes. Moreover, the strategy can also be used for the synthesis of thiophenes from 1,4-diaryl-1,3-dienes.
One-pot synthesis of 1,3-diaryl but-1-enes from 1-arylethanols over Snβ zeolite
作者:Naresh Mameda、Krishna Sai Gajula、Swamy Peraka、Srujana Kodumuri、Durgaiah Chevella、Rammurthy Banothu、Vasu Amrutham、Narender Nama
DOI:10.1016/j.catcom.2016.11.026
日期:2017.2
for the one-potsynthesis of 1,3-diaryl but-1-enes from 1-arylethanols via dehydration of 1-arylethanols followed by head-to-tail dimerization of vinylarenes over heterogeneous catalyst (Snβ zeolite). The scope of the reaction was explored for various 1-arylethanols and afforded the corresponding dimers in good to excellent yields with high regio- and stereoselectivity. Moreover, Snβ zeolite could be