A Surprising Switch from the Myers–Saito Cyclization to a Novel Biradical Cyclization in Enyne–Allenes: Formal Diels–Alder and Ene Reactions with High Synthetic Potential
摘要:
AbstractIf there is an aryl substituent on the acetylene terminus of enyne‐allenes, then its reaction mode may be changed from the Myers‐Saito cyclization to a novel C2–C6 cyclization resulting in a net intramolecular Diels‐Alder or ene reaction. As a consequence, the thermal cyclization of readily accessible acyclic enyne‐allenes can be utilized for the synthesis of complex benzofulvene and benzofluorene derivatives. Kinetic results of the C2–C6 cyclization reaction indicate a two‐step reaction pathway with a benzofulvene biradical intermediate.
Gold-Catalyzed Cyclization of 1,6-Diyne-4-en-3-ols: Stannyl Transfer from 2-Tributylstannylfuran Through Au/Sn Transmetalation
作者:Yifeng Chen、Ming Chen、Yuanhong Liu
DOI:10.1002/anie.201201523
日期:2012.6.18
Gold‐tinted: A gold catalyzed cyclization reaction of 1,6‐diyne‐4‐en‐3‐ols, incorporating an in situ stannyltransfer reaction involving 2‐tributylstannylfuran, gives synthetically valuable 2‐stannylnaphthalenes (see scheme; DCE=dichloroethane). A gem‐diaurated furan complex, was isolated and fully characterized by X‐ray crystallographic analysis, and provides strong evidence for a tin to gold transmetalation
Cobalt-catalyzed regioselective syntheses of indeno[2,1-<i>c</i>]pyridines from nitriles and diynes bearing propargyl fragments
作者:Murong Xu、Zhong Zheng、Mengdan Wang、Lingkai Kong、Yujuan Ao、Yanzhong Li
DOI:10.1039/c8ob02419g
日期:——
highly efficient CoI2/o-phenanthroline catalyzed cycloaddition reaction of diynes bearing TBS protected propargylicalcohol fragments with nitriles has been developed. This methodology offers regioselective access, with good functional group tolerance, to various indeno[2,1-c]pyridine derivatives in moderate to excellent yields. It was found that o-phenanthroline as a bidentate nitrogen ligand showed
已开发出一种高效的CoI 2 /邻菲咯啉催化带有TBS保护的炔丙醇片段的丁炔与腈的环加成反应。该方法以中等至优异的产率提供了对多种茚并[2,1- c ]吡啶衍生物的区域选择性通路,具有良好的官能团耐受性。发现邻菲咯啉作为二齿氮配体在该环加成反应中显示出高功效。
Gold-Catalyzed Cascade Cyclizations of 1,6-Diynyl Carbonates to Benzo[b]fluorenes Involving Arylation of Oxocarbenium Ion Intermediates and Decarboxylative Etherification
作者:Yifeng Chen、Ming Chen、Yuanhong Liu
DOI:10.1002/anie.201201799
日期:2012.6.25
cycloisomerizations give access to highly substituted benzo[b]fluorenes under mild reaction conditions (see scheme). Experimental results indicate that the in situ formed oxocarbeniumionintermediates, derived from gold‐catalyzed 3,3‐rearrangement and 6‐endo‐dig cyclization, undergo intramolecular arylation and subsequent decarboxylativeetherification to furnish the final ether products.
重排:在温和的反应条件下,所描述的金催化的环异构化反应可得到高度取代的苯并[ b ]芴(参见方案)。实验结果表明,在原位形成oxocarbenium离子中间体,衍生自金催化3,3-重排和6-内-挖环化,分子内经历芳基化和随后的脱羧醚化,得到最终的醚产物。
Gold-Catalyzed Cascade Friedel-Crafts/Furan-Yne Cyclization/Heteroenyne Metathesis for the Highly Efficient Construction of Phenanthrene Derivatives
作者:Yifeng Chen、Guijie Li、Yuanhong Liu
DOI:10.1002/adsc.201000644
日期:2011.2.11
A rapid access to highly substituted phenanthrenyl ketones through gold-catalyzedcyclization of 1,6-diyn-4-en-3-ols with furans has been developed. Gold catalysts are effective to catalyze three cascade processes involving Friedel–Crafts/furan-ynecyclization/heteroenynemetathesis through CO bond and alkyne activation. This method offers several advantages such as high selectivities and easily accessible
Gold(I)-Catalyzed Regioselective Cyclization to Access Cyclopropane-Fused Tetrahydrobenzochromenes
作者:Perla Bharath Kumar、Chittala Emmaniel Raju、Patel Hinal Chandubhai、Balasubramanian Sridhar、Galla V. Karunakar
DOI:10.1021/acs.orglett.2c02564
日期:2022.9.23
Gold(I)-catalyzedefficient synthetic transformation was achieved to access the tetrahydrobenzo[h]cyclopropa[c]chromenes from allyl-substituted 1,6-diynes. Cyclopropane-fused tetrahydrobenzochromenes were obtained regioselectively in ≤92% yields. In this atom-economic organic transformation, three new C–C bonds were formed sequentially in one pot.
实现了金(I)催化的高效合成转化,以从烯丙基取代的 1,6-二炔中获得四氢苯并[ h ]环丙[ c ]色烯。以≤92% 的产率区域选择性地获得了环丙烷稠合的四氢苯并色烯。在这种原子经济有机转化中,三个新的 C-C 键在一锅中依次形成。