Functionalization of Csp3–H bond—Sc(OTf)3-catalyzed domino 1,5-hydride shift/cyclization/Friedel–Crafts acylation reaction of benzylidene Meldrum’s acids
摘要:
Under Sc(OTf)(3) catalysis, benzylidene Meldrum's acids bearing a tethered p-methoxyphenethyl group were observed to undergo a [1,5]-hydride shift/cyclization at room temperature, representing a mild Csp(3)-H bond functionalization. The resulting spiro Meldrum's acid intermediates then underwent intramolecular Friedel-Crafts acylation, completing the one-pot, domino reaction. The reported protocol generates the 6-6-5-6 tetracyclic core of tetrahydrobenzo[b]fluoren-11-ones. (C) 2009 Elsevier Ltd. All rights reserved.
Synthesis of Pyrrolo[1,2-<i>b</i>]isoquinolines via Gold(I)-Catalyzed Cyclization/Enyne Cycloisomerization/1,2-Migration Cascade
作者:Liangliang Song、Guilong Tian、Luc Van Meervelt、Erik V. Van der Eycken
DOI:10.1021/acs.orglett.0c02310
日期:2020.8.21
of the migrating group is comprehensively investigated. The study of the mechanism indicates that the pathway involving a gold carbenoid species is the main pathway and that the 1,2-migration of alkyl and aryl groups to the gold carbenoid occurs in an intramolecular fashion. This cascade reaction is also employed as the key step for the synthesis of a decumbenine B analogue.
A strategy for the synthesis of spiroketal compounds through a tandem iodocyclization of 1-(2-ethynylphenyl)-4-hydroxybut-2-yn-1-one derivatives is presented. This reaction could proceed under very mild conditions in a short time and avoid the use of expensive and toxic metal catalysts. Moreover, the resulting halides can be further exploited by subsequent palladium-catalyzed coupling reactions, which
Silver‐Catalyzed Sequential Cascade Reaction of Isocyanides with 1‐(2‐Ethynyl‐phenyl)‐prop‐2‐yn‐1‐ol: Access to Benzo[
<i>b</i>
]fluorenes and Benzofuran‐Pyrroles
作者:Jian‐Quan Liu、Xinyi Chen、Xuanyu Shen、Yihan Wang、Xiang‐Shan Wang、Xihe Bi
DOI:10.1002/adsc.201801344
日期:2019.4
A silver‐catalyzed cycloaromatization of 1‐(2‐ethynyl‐phenyl)‐prop‐2‐yn‐1‐ol with isocyanides efficiently provides benzo[b]fluorene and benzofuran‐pyrrole derivatives through a modular cascade reaction that includes a nucleophilic attack on the diyne substrate. A C−C cross‐coupling/oxygen transportation/Diels‐Alder/hydrogen shift/isomerization cascade mechanistic pathway is proposed.
银与异氰酸酯催化的1-(2-乙炔基-苯基)-丙-2-炔-1-醇的芳环芳香化反应可通过模块级联反应有效地提供苯并[ b ]芴和苯并呋喃-吡咯衍生物,包括对苯并的亲核攻击。二炔底物。提出了AC-C交叉偶联/氧迁移/ Diels-Alder /氢转移/异构化级联机制途径。
Visible-Light Photocatalytic Bicyclization of 1,7-Enynes toward Functionalized Sulfone-Containing Benzo[<i>a</i>
]fluoren-5-ones
A new visible‐light photocatalytic arylsulfonylation and bicyclization of C(sp3)‐tethered 1,7‐enynes with sulfinic acids has been developed, delivering functionalized sulfone‐containing benzo[a]fluoren‐5‐ones with generally good yields. This Eosin Y‐catalyzed approach makes use of visible light as a safe and eco‐friendly energy source to drive cascade cyclization reactions, resulting in continuous
已开发出一种新的可见光光催化芳基磺酰化和C(sp 3)系的1,7-烯炔与亚磺酸的双环化,可提供官能化的含砜苯并[ a ]芴-5酮,且收率普遍良好。这种曙红Y催化方法利用可见光作为一种安全且生态友好的能源来驱动级联环化反应,从而导致连续的多个成键事件(包括C–S和C–C键)有效地构建多环连接的烷基芳基砜。
Gold-Catalyzed Cyclization of 2-Alkynylaldehyde Cyclic Acetals via Hydride Shift for the Synthesis of Indenone Derivatives
作者:Tsuyoshi Yamada、Kwihwan Park、Takumu Tachikawa、Akiko Fujii、Matthias Rudolph、A. Stephen K. Hashmi、Hironao Sajiki
DOI:10.1021/acs.orglett.0c00221
日期:2020.3.6
An efficient gold-catalyzed cyclization of 2-alkynylaldehyde cyclic acetals has been developed for the synthesis of indenone derivatives. A wide variety of functionalized indenone derivatives can be obtained in good-to-excellent yields. HMBC and NOESY NMR analyses and mechanistic elucidation experiments revealed that the cyclization occurs via a 1,5-H shift. The cyclic acetal group promoted the 1,5-H