Total synthesis of penta-Me amurensin H and diptoindonesin G featuring a Rh-catalyzed carboacylation/aromatization cascade enabled by C C activation
摘要:
Oligostilbenoids represented a family of natural products, which contained one or several multifused benzofuran substructures and displayed promising biological activities towards cancer as well as immunological therapeutic targets. A convergent-divergent strategy featuring Rh-catalyzed carboacylation/aromatization cascade reaction based on C-C activation of benzocyclbutenones had been conceived. penta-Methyl amurensin H and diptoindolnesin G were successfully synthesized without any protecting groups, constituting a new entry towards oligostilbenoids' natural product synthesis. The synthesis completed within 10 steps for both natural products, suggesting conciseness and efficacy of the C-C activation in complex natural product synthesis. (C) 2019 Elsevier Ltd. All rights reserved.
Site‐Selective C–C Cleavage of Benzocyclobutenones Enabled by a Blocking Strategy Using Nickel Catalysis
作者:Jing‐Hong Guo、Yu Liu、Xin‐Cheng Lin、Tian‐Mu Tang、Bi‐Qin Wang、Ping Hu、Ke‐Qing Zhao、Feijie Song、Zhang‐Jie Shi
DOI:10.1002/anie.202106709
日期:2021.8.23
Controlling the chemo- and regioselectivity of transition-metal-catalyzed C−C activation remains a great challenge. The transformations of benzocyclobutenones (BCBs) usually involve the cleavage of C1−C2 bond. In this work, an unprecedented highly selective cleavage of C1−C8 bond with the insertion of alkynes is achieved by using blocking strategy via Ni catalysis, providing an efficient method for
Controlling the behavior of terminalalkynes in metal-catalyzed intermolecular tandem reactions is a formidable challenge despite the potential advantage offered by these strategies in modern synthesis. Herein, we describe that a nickel catalyst enables a tandem process involving the rapid dimerization of terminalalkynes into 1,3-enynes and the cycloaddition of these intermediates with an azetidinone
Thermal <i>Hetero</i>-Diels–Alder Reaction of Benzocyclobutenones with Isatins To Form 2-Oxindole Spirolactones
作者:Thomas Wurm、Ben W. H. Turnbull、Brett R. Ambler、Michael J. Krische
DOI:10.1021/acs.joc.7b02769
日期:2017.12.15
or “ortho-quinoid ketene methides”, which engage in intermolecular [4+2] cycloadditions with isatins 2a–2f to form 2-oxindole spirolactones 3a–3l. This process tolerates an array of different functional groups and substitution patterns, and is applicable to unprotected isatins 2b–2f bearing free NH-functionalities. The superior performance of isatins compared to other carbonyl based dienophiles was
Pd/C-Catalyzed Stereoselective Arene Hydrogenation of Benzocyclobutenes Enabled by π-Bond Localization
作者:Zhan Shi、Licheng Lu、Ping Lu
DOI:10.1021/acs.orglett.4c01737
日期:2024.6.28
We developed here a Pd/C-catalyzed diastereoselective cis-hydrogenation of benzocyclobutene derivatives under mild conditions to deliver an array of bicyclo[4.2.0]octane scaffolds with up to five stereocenters. The π-bond localization enabled hydrogenation of the arene moiety to occur even at roomtemperatureunder1atm of a H2 atmosphere.
Rapid, convergent, and regioselective synthesis of anthracenes
作者:John J. Fitzgerald、Neville E. Drysdale、R. A. Olofson
DOI:10.1021/jo00052a027
日期:1992.12
Anthracenes are obtained in moderate to good yield by the simultaneous treatment of benzocyclobutenols and halobenzenes with LTMP in tetrahydropyran. In the key step of this one-pot process, o-toluoyl anion intermediates from the known ring-opening of benzocyclobutenoxides add to halobenzene derived arynes. Methoxy-substituted benzocyclobutenols which are readily made regiospecifically by known methods also react regiospecifically with the single benzyne generated from either a 2- or 3-haloanisole. For example, the only trimethoxyanthracene isolated (48% yield) from the reaction of 6-methoxybenzocyclobutenol (8) with 5-chloro-1,3-dimethoxybenzene is the 1,3,8-isomer 20. When 1,2-dihydrocyclobuta[l]phenanthren-1-ol (14) and/or halonaphthalenes are the reactants, benzannulated anthracenes are formed; e.g., tribenz[a,c,h]anthracene in 68% yield from 14 and bromonaphthalene. In another extension, pentaphene (31) was made in one pot from o-dichlorobenzene.