Synthesis of Exocyclic Trisubstituted Alkenes
<i>via</i>
Nickel‐ Catalyzed Kumada‐Type Cross‐Coupling Reaction of
<i>gem</i>
‐ Difluoroalkenes with Di‐Grignard Reagents
作者:Wenpeng Dai、Xuxue Zhang、Juan Zhang、Yingyin Lin、Song Cao
DOI:10.1002/adsc.201500889
日期:2016.1.21
A practical, nickel‐catalyzed Kumada‐type double cross‐coupling reaction of gem‐difluoroalkenes with 1,4‐ or 1,5‐di‐Grignard reagents was developed. The reaction proceeded efficiently at room temperature and a variety of cyclization products, arylmethylenecyclopentanes and arylmethylenecyclohexanes, were obtained in high to excellent yields, respectively.
Alkenylation of thiophenes at the 2-position with magnesium alkylidene carbenoids
作者:Tsuyoshi Satoh、Natsuki Mori、Kazumi Obuchi
DOI:10.1016/j.tetlet.2007.07.074
日期:2007.9
Treatment of magnesium alkylidene carbenoids, generated from 1-chlorovinyl p-tolyl sulfoxides with isopropylmagnesiurn chloride at -78 degrees C in toluene, with 2-lithiothioplienes gave 2-alkenylated thiophenes in good to high yields. The intermediate of this reaction was found to be an alkenylmagnesium, which could be trapped with iodoalkanes and ethyl chloroformate. This procedure offers a novel and efficient one-pot synthesis of thiophenes having a disubstituted or a trisubstittited olefin at the 2-position from thiophenes in good yields. (c) 2007 Elsevier Ltd. All rights reserved.
Harnessing Applied Potential: Selective β-Hydrocarboxylation of Substituted Olefins
作者:Anas Alkayal、Volodymyr Tabas、Stephanie Montanaro、Iain A. Wright、Andrei V. Malkov、Benjamin R. Buckley
DOI:10.1021/jacs.9b13305
日期:2020.1.29
The construction of carboxylic acid compounds in a selective fashion from low value materials such as alkenes remains a long-standing challenge to synthetic chemists. In particular, β-addition to styrenes is underdeveloped. Herein we report a new electrosynthetic approach to the selective hydrocarboxylation of alkenes that overcomes the limitations of current transition metal and photochemical approaches
Alkenylation of thiophenes and furans at the 2-position and a synthesis of allenes conjugated with α,β-unsaturated ester with magnesium alkylidene carbenoids
to afford thiophenes and furans bearing a fully substituted alkene at the 2-position. Treatment of the magnesium alkylidene carbenoids with 2-lithio-5-methoxyfuran afforded allenes conjugated with α,β-unsaturated methyl ester in moderate yields. These procedures offer a new and versatile one-pot synthesis of 2-alkenylthiophenes, 2-alkenylfurans, and allenes conjugated with α,β-unsaturated methyl ester