Osmium-Catalyzed 7-endo Heterocyclization of Aromatic Alkynols into Benzoxepines
作者:Alejandro Varela-Fernández、Cristina García-Yebra、Jesús A. Varela、Miguel A. Esteruelas、Carlos Saá
DOI:10.1002/anie.201000455
日期:——
The wizard of Os: Regioselective osmium‐catalyzed 7‐endo heterocyclization of aromaticalkynols affords benzoxepines in good yields. The proposed catalytic cycle involves the key formation of osmium–vinylidene complexes via an alkynyl‐hydride–osmium(IV) complex from the starting alkynol.
Efficient <i>endo</i>
Cycloisomerization of Terminal Alkynols Catalyzed by a New Ruthenium Complex with 8-(Diphenylphosphino)quinoline Ligand and Mechanistic Investigation
including [RuCl2(DPPQ)2] (1), [Ru(μ‐Cl)(DPPQ)2]2(BPh4)2 (2), and [RuCl(DPPQ)2Py](BF4) (3). Complex 2, with only 1 mol % loading, was found to be catalytically active for the endo cycloisomerization of various terminal alkynols to endo‐cyclic enolethers in moderate to excellent yields. In particular, the 7‐ and 8‐endo heterocyclization can be achieved efficiently to give the seven‐membered 3‐benzoxepine and
合成了几种新的由P,N-供体配体8-(二苯基膦基)喹啉(DPPQ)支撑的钌配合物,包括[RuCl 2(DPPQ)2 ](1),[Ru(μ-Cl)(DPPQ)2 ]。2(BPh 4)2(2)和[RuCl(DPPQ)2 Py](BF 4)(3)。复杂2,仅1摩尔%的负载,被发现是用于催化活性的内切各种终端炔醇向环异构远藤在温和-环烯醇醚到优异的产率。特别是7-和8-内酯可以有效地实现杂环化,从而得到七元3-苯并xepine和八元3-苯并[ d ]氧辛酸衍生物。已经进行了2与各种炔醇底物的化学计量反应,以研究机理,从而导致了包括[RuCl(DPPQ)2 = CCH 2 C 6 H 4 CH 2 CH 2 O}](BPh 4)(12)和[RuCl(DPPQ)2 = CCH 2(CH 2)n CH 2 O}](BPh 4)(n = 3,12' ; n = 2,13 ; n = 1,14)。oxa
Carbofunctionalization of Terminal Alkynes via Rhodium Catalysis Enabling Formations of Four Different Bonds
作者:Dae-Kwon Kim、Minjung Keum、Heekyung Yun、Insu Kim、Jung Min Joo、Chulbom Lee
DOI:10.1021/acs.orglett.3c00341
日期:2023.3.31
disubstituted rhodium vinylidene complex is generated upon C–C bond formation at the terminal alkyne with tethered electrophiles such as alkyl halides, aldehydes, imines, and Michael acceptors. Subsequent intermolecular transfer oxygenation of the rhodium vinylidene with pyridine N-oxide generates a rhodium-complexed ketene intermediate that reacts with a variety of heteroatom nucleophiles to give rise to cyclic