Cyano-Schmittel Cyclization through Base-Induced Propargyl-Allenyl Isomerization: Highly Modular Synthesis of Pyridine-Fused Aromatic Derivatives
作者:Xu You、Xin Xie、Haoyi Chen、Yuxue Li、Yuanhong Liu
DOI:10.1002/chem.201503374
日期:2015.12.14
cyano‐Schmittel cyclization of in situ‐generated cyano‐allenes has been carried out. The DFT calculation results suggest that the diradical pathway plays a major role in this cyclization. The reactions can be conveniently performed in a one‐pot manner through cascade Sonogashira coupling of terminal cyano‐ynes with organic halides, followed by base‐promoted propargyl‐allenyl isomerization/cyclization, leading
Trichlorophenyl Formate: Highly Reactive and Easily Accessible Crystalline CO Surrogate for Palladium-Catalyzed Carbonylation of Aryl/Alkenyl Halides and Triflates
作者:Tsuyoshi Ueda、Hideyuki Konishi、Kei Manabe
DOI:10.1021/ol302593z
日期:2012.10.19
The high utility of 2,4,6-trichlorophenyl formate, a highly reactive and easilyaccessible crystalline CO surrogate, is demonstrated. The decarbonylation with NEt3 to generate CO proceeded rapidly at rt, thereby allowing external-CO-free Pd-catalyzed carbonylation of aryl/alkenyl halides and triflates. The high reactivity of the CO surrogate enabled carbonylation at rt and significantly reduced the
Ring Opening of 2,5-Didehydrothiophene: Matrix Photochemistry of C<sub>4</sub>H<sub>2</sub>S Isomers
作者:Yong Seol Kim、Hiroshi Inui、Robert J. McMahon
DOI:10.1021/jo061678l
日期:2006.12.1
energy surface. The photochemical formation of thioketene 6 from either diyl 4 or sulfide 3 may be interpreted in line with a recent computational prediction on the thermal ring opening of diyl 4, which favors C−S bond cleavage, leading to 6, over C−C bond cleavage, leading to 3. Photolysis of matrix-isolated 3,4-thiophenedicarboxylic acid anhydride (11) enables the observation of the photoequilibration
基质分离的2,5-二碘噻吩(10)的辐照(λ> 254 nm)产生分配给乙炔基硫代乙烯酮(6)的IR谱带。二乙炔硫醚(3),这将形成初期2,5- didehydrothiophene(的复古伯格曼环化反应的过程4)时,没有检测到。在相同的照射条件下,基质分离的二乙炔基硫醚(3)重排为硫代乙烯酮6和丁三烯硫酮(5),这是C 4 H 2 S势能表面上的全局最小值。由二基4或硫化物3形成硫代烯酮6的光化学形成可以根据对二基4的热开环的最新计算预测来解释,这相对于C-C键断裂(导致3)更有利于C-S键断裂(导致6)。基质分离的3,4-噻吩二羧酸酐(11)的光解使得能够观察到三种低能C 4 H 2 S异构体,丁三烯硫酮(5),乙炔基硫代乙烯酮(6)和丁二炔基硫醇(7)的光平衡。明显的[1,3]-氢转移。
Dual-Emissive Platinum(II) Metallacycles with Thiophene-Containing Bisacetylide Ligands
作者:Yang Cao、Michael O. Wolf、Brian O. Patrick
DOI:10.1021/acs.inorgchem.6b01464
日期:2016.9.6
Three cis-diphosphino Pt(II) metallacycles with thiophene-containing bisacetylide ligands were synthesized and their absorption and emission properties examined. These properties are explained by DFT and TD-DFT analysis of ground-state as well as singlet- and triplet-state energies and geometries. Two of the metallacycles show room-temperature dual emission (fluorescence and phosphorescence) with different
Base-Catalyzed Cyclization of 1,6-Diynyl Carboxylates Involving Propargyl-Allenyl Isomerization: Efficient Synthesis of Benzo[<i>b</i>]fluorene and Its Analogues
作者:Ning Sun、Xin Xie、Gaonan Wang、Haoyi Chen、Yuanhong Liu
DOI:10.1002/adsc.201601074
日期:2017.4.17
An efficient protocol for the synthesis of benzo[b]fluorenes via base‐catalyzed cyclization of 1,6‐diynyl carbonates, esters or ethers has been developed. The reaction likely proceeds via base‐induced propargyl‐allenyl isomerization followed by Schmittel‐type cyclization. Heterocycle‐fused fluorenes such as thiophene‐ or pyridine‐fused substrates could also be conveniently constructed by this method
已开发出一种通过碱催化的1,6-二炔基碳酸酯,酯或醚的环化反应合成苯并[ b ]芴的有效方案。该反应可能是通过碱诱导的炔丙基-烯基异构化,然后是施密特尔型环化而进行的。杂环融合的芴,例如噻吩或吡啶融合的底物也可以通过这种方法方便地构建。该反应的合成效用通过最多制备七环稠合多环芳烃得到了证明。