Rhodium-Catalyzed Oxidative Coupling of Triarylmethanols with Internal Alkynes via Successive C−H and C−C Bond Cleavages
摘要:
[GRAPHICS]The rhodium-catalyzed oxidative coupling of triarylmethanols with internal alkynes effectively proceeds in a 1:2 manner via cleavage of C-H and C-C bonds to produce the corresponding naphthalene derivatives. Addition of trior tetraphenylcyclopentadiene as a ligand is crucial for the reaction to occur efficiently.
O-Dihaloarenes as aryne precursors for nickel-catalyzed [2 + 2 + 2] cycloaddition with alkynes and nitriles
作者:Jen-Chieh Hsieh、Chien-Hong Cheng
DOI:10.1039/b801870g
日期:——
o-Dihaloarenes acting as aryne precursors react with acetylenes and nitriles catalyzed by the NiBr(2)(dppe)/dppe/Zn system to give substituted naphthalene, phenanthridine or triphenylene derivatives depending on the reaction conditions in moderate to excellent yields with good tolerance of functional groups.
involve chlororhodation to the alkynes by the intermediary arylchlororhodium(III) species generated in situ followed by reductive elimination of the products, which are suggested by the results of some control experiments. In contrast to the reaction with terminal alkynes, that with some internal ones proceeds without decarbonylation to produce 2,3-disubstituted-1-indenones as the predominant products.
The rhodium(I)-catalyzed reaction of alkynes with 2-bromophenylboronic acids in the presence of paraformaldehyde resulted in a CO gas-free carbonylative cyclization, yielding indenone derivatives. [RhCl(BINAP)]2 and [RhCl(cod)]2 were responsible for the decarbonylation of formaldehyde and the subsequent carbonylation of alkynes with 2-haloboronic acids, respectively, leading to efficient whole carbonylation
reaction of alkynes with 2-bromophenylboronic acids under nitrogen gives naphthalene derivatives, in which two molecules of alkynes are incorporated. A vinylrhodium complex similar to II can also be generated by a different route by employing 2-bromophenyl(trimethylsilyl)acetylene and arylboronic acids in the presence of Rh(I) complex as the catalyst, resulting in the formation of indenones. The reaction
Group 4 Diarylmetallocenes as Bespoke Aryne Precursors for Titanium-Catalyzed [2 + 2 + 2] Cycloaddition of Arynes and Alkynes
作者:Benjamin R. Reiner、Ian A. Tonks
DOI:10.1021/acs.inorgchem.9b01082
日期:2019.8.19
reports describing titanium (Ti)-catalyzed [2 + 2 + 2] cyclotrimerization of alkynes, the incorporation of arynes into this potent manifold has never been reported. The in situ generation of arynes often requires fluoride, which instead will react with the highly fluorophilic Ti center, suppressing productive catalysis. Herein, we describe the use of group 4 diarylmetallocenes, CpR2MAr2 (CpR = C5H5,
尽管有大量报道描述了钛(Ti)催化炔烃的[2 + 2 + 2]环三聚反应,但从未报道过将芳烃掺入到这种有效的歧管中。芳烃的原位生成通常需要氟化物,而氟化物将与高度氟的Ti中心反应,从而抑制生产催化。在这里,我们描述了使用第4组二芳基金属茂CpR2MAr2(CpR = C5H5,C5Me5; M = Ti,Zr)作为芳烃前体,通过与2当量的炔烃偶合,进行Ti催化的取代萘的合成。催化剂负载量为1%时,可获得所需萘产品的中等至良好收率,这比钯或镍催化的类似反应低约一个数量级。此外,萘在电子产品,光伏产品,和制药业,敦促发现更多的经济综合体。这些结果表明,芳烃从CpR2M(η2-芳烃)配合物转移到另一种金属是将芳烃片段引入有机金属催化过程的可行途径。