Copper(<scp>i</scp>)-catalyzed [4 + 2] cycloaddition of aza-<i>ortho</i>-quinone methides with bicyclic alkenes
作者:Lu Lei、Yu-Feng Liang、Cui Liang、Jiang-Ke Qin、Cheng-Xue Pan、Gui-Fa Su、Dong-Liang Mo
DOI:10.1039/d1ob00319d
日期:——
tetrahydroquinoline-fused bicycles bearing multiple stereocenters are prepared in good yields with high diastereoselectivity through Cu2O-catalyzed [4 + 2] cycloaddition of aza-ortho-quinone methides (ao-QMs) with bicyclicalkenes. Mechanistic studies reveal that the Cu(I) catalyst not only promotes the formation of ao-QMs through a radical process by single electron transfer but also accelerates [4 + 2] cycloaddition
通过 Cu 2 O 催化的 [4 + 2] 氮杂邻醌甲基化物 (a o -QMs) 与双环烯烃的环加成反应,以良好的收率和高非对映选择性制备了多种具有多个立体中心的四氢喹啉稠合双环化合物。机理研究表明,Cu( I )催化剂不仅通过单电子转移的自由基过程促进a o -QMs的形成,而且还加速了[4 + 2]环加成反应。该反应很容易以克级进行,并且获得的四氢喹啉融合的自行车可以转化为不同的四氢喹啉支架。
(Phenyl)[o-(trimethylsilyl)phenyl]iodonium triflate. A new and efficient precursor of benzyne
作者:Tsugio Kitamura、Masakatsu Yamane
DOI:10.1039/c39950000983
日期:——
(Phenyl)[o-(trimethylsilyl)phenyl]iodonium triflate readily prepared from o-bis(trimethylsilyl)benzene and the hypervalent iodine(III) reagent [Phl(OAc)2·2TfOH] shows excellent formation of benzyne under mild and neutral conditions and efficiently provides adducts with typical trapping agents, e.g. furan, anthracene, diphenylisobenzofuran and tetraphenylcyclopentadienone.
Synthesis of Novel Tetracycles via an Intramolecular Heck Reaction with <i>a</i><i>nti</i>-Hydride Elimination
作者:Mark Lautens、Yuan-Qing Fang
DOI:10.1021/ol035354k
日期:2003.10.1
[reaction: see text] The catalytic combination of Pd(2)(dba)(3)/HP(t-Bu)(3).BF(4) and DABCO gives an unusual intramolecular Heck reaction with dihydronaphthalene substrates, yielding formal anti-hydride elimination products in good to excellent yields under mild conditions. For dibromo substrates, multiple Heck reactions are possible when an external acceptor is added to afford more highly functionalized