1566-67-2Relevant articles and documents
Stereoselective synthesis of enol acetates by the reaction of alkenylboronates with (diacetoxyiodo)benzene and sodium iodide
Murata, Miki,Satoh, Kaname,Watanabe, Shinji,Masuda, Yuzuru
, p. 1465 - 1466 (1998)
Stereochemically pure (E)- and (Z)-alk-1-en-1-yl acetates have been easily prepared by acetoxylation of the (Z)-and (E)-alk-1-en-1-ylboronic acids or their esters, respectively, with (diacetoxyiodo)benzene and sodium iodide, in reasonable yields.
Carboxylic acid addition to terminal alkynes utilizing ammonium tagged Hoveyda-Grubbs catalyst supported on magnetically separable core/shell silica: A highly reusable and air compatible catalytic system
?ztürk, Bengi ?zgün,Gürcü, Didar,?ehito?lu, Solmaz Karabulut
, p. 11 - 16 (2019/01/24)
In this study, the performance of ammonium tagged Hoveyda-Grubbs catalyst supported on magnetically separable core/shell silica gel was tested on carboxylic acid addition reactions to terminal alkynes using a variety of carboxylic acid derivatives under air atmosphere. The catalytic system was found to be compatible with air atmosphere and can tolerate even non-degassed solvents. The reaction parameters such as temperature, substrate/catalyst ratio and the effect of carboxylic acid on the selectivity and yield of the reaction were investigated in details. The reaction of arylacetylenes with acetic acid yielded the corresponding E-isomer with conversion values up to 99% with a catalytic loading of 1% Ru. The reusability of the catalyst was tested using acetic acid/benzoic acid and phenylacetylene in toluene at 85 °C under air atmosphere. The catalyst was found to be highly reusable and maintained its activity up to 11th run, reaching a conversion value of 83% with minimum ruthenium leaching.
Stereoselective Synthesis of Vinylboronates by Rh-Catalyzed Borylation of Stereoisomeric Mixtures
Li, Shenhuan,Li, Jie,Xia, Tianlai,Zhao, Wanxiang
supporting information, p. 462 - 468 (2019/03/28)
The stereoselective preparation of vinylboronates via rhodium-catalyzed borylation of E/Z mixtures of vinyl actetates is described, and this method was also extended to synthesis of vinyldiboronates. These transformations feature high functional group compatibility and mild reaction conditions. Control experiments support a mechanism that involved a Rh-catalyzed borylation-isomerization sequence. The isomerization of (Z)-vinylboronates to (E)-isomers was also demonstrated.
Cationic ruthenium complex of the formula [RuCl(2,6-diacetylpyridine)(PPh3)2]BArF and its catalytic activity in the formation of enol esters
Stark, Matthew J.,Tang, Douglas T.,Rath, Nigam P.,Bauer, Eike B.
supporting information, p. 873 - 877 (2018/02/09)
A new ruthenium 2,6-diacetylpyridine complex was synthesized and applied in the atom-economic synthesis of enol esters through Markovnikov-directed addition of carboxylic acids to terminal alkynes. The ruthenium complex [RuCl(dap)(PPh3)2]+BArF? was synthesized from [RuCl2(PPh3)2] and the corresponding ligand 2,6-diacetylpyridine (dap). The complex was characterized structurally. The new ruthenium complex was utilized under ambient conditions as a catalyst in the Markovnikov addition of carboxylic acids to terminal alkynes to afford the corresponding enol esters in 93% to 52% isolated yields (85 °C, 16 h reaction time, 1 mol% catalyst loading).
Iron-Catalyzed Cross-Coupling of Alkenyl Acetates
G?rtner, Dominik,Stein, André Luiz,Grupe, Sabine,Arp, Johannes,Von Wangelin, Axel Jacobi
supporting information, p. 10545 - 10549 (2015/09/02)
Stable C-O linkages are generally unreactive in cross-coupling reactions which mostly employ more electrophilic halides or activated esters (triflates, tosylates). Acetates are cheap and easily accessible electrophiles but have not been used in cross-couplings because the strong C-O bond and high propensity to engage in unwanted acetylation and deprotonation. Reported herein is a selective iron-catalyzed cross-coupling of diverse alkenyl acetates, and it operates under mild reaction conditions (0 C, 2 h) with a ligand-free catalyst (1-2 mol%). Iron clad: Acetates are underutilized electrophiles in metal-catalyzed cross-coupling reactions because of the strong alkenyl C-O bond and their propensity to engage in unwanted reactions. Combination of a ligand-free low-valent Fe catalyst with nucleophilic organomagnesium reagents, low temperature, and short reaction times results in highly selective cross-couplings with alkenyl acetates.
Palladium-Catalyzed Arylation of Olefins by Triarylphosphines via C-P Bond Cleavage
Lu, Dapeng,Xu, Yu,Liu, Wenjing,Guo, Lijuan,Sun, Xingxia
, p. 116 - 122 (2015/10/19)
C-H Arylation of olefins by triarylphosphines via C-P bond cleavage has been achieved with either Pd0 or PdII catalysts. A variety of olefins and triarylphosphines are tolerated, and we inferred that both Pd0 and PdII could function directly without pre-oxidation or pre-reduction.
A dinuclear ruthenium catalyst with a confined cavity: Selectivity in the addition of aliphatic carboxylic acids to phenylacetylene
Cheung, Kwong-Chak,Wong, Wing-Leung,So, Ming-Him,Zhou, Zhong-Yuan,Yan, Siu-Cheong,Wong, Kwok-Yin
supporting information, p. 710 - 712 (2013/03/13)
A dinuclear ruthenium catalyst with a rigid anthracene spacer shows excellent regio- and stereo-selectivity in the atom-economic addition of aliphatic carboxylic acids to phenylacetylene, producing exclusively anti-Markovnikov enol-esters with high E/Z ratios of the isomers.
Synthesis and structure of [Ru(dppe)2(CH3CN)Cl] [BPh4] and its catalytic application to anti-Markovnikov addition of carboxylic acids to terminal alkynes
Das, Uttam Kumar,Bhattacharjee, Manish
experimental part, p. 78 - 82 (2012/03/12)
The compound, [Ru(dppe)2(CH3CN)Cl][BPh4] (1) has been synthesized from the precursor complex, [(PPh3) 2Ru(CH3CN)3Cl][BPh4]. The complex has been structurally character
Steric control at the wingtip of a bis-N-heterocyclic carbene ligand: Coordination behavior and catalytic responses of its ruthenium compounds
Saha, Sayantani,Ghatak, Tapas,Saha, Biswajit,Doucet, Henri,Bera, Jitendra K.
, p. 5500 - 5505 (2012/11/07)
Changing the N-substituents of a methylene-linked bis-NHC ligand from n-butyl to bulky mesityl shifts ligand coordination from normal/normal to normal/abnormal mode. The mesityl wingtip groups afford [RuII( MesNHC(CH2)NHC
Ligand-controlled regio- and stereoselective addition of carboxylic acids onto terminal alkynes catalyzed by carbonylruthenium(0) complexes
Tan, Sze Tat,Fan, Wai Yip
experimental part, p. 4631 - 4635 (2011/02/27)
The addition of carboxylic acids onto terminal alkynes was catalyzed by mononuclear ruthenium(0) complexes to give enol esters in high yields. By using ligands with different electronic properties, product selectivity was achieved. E-enol esters were preferentially produced when tricarbonyl(η4- diene)ruthenium complexes were used; while geminal enol esters were produced when tricarbonylbis(phosphane)ruthenium complexes were used. Product selectivity is a major problem in transition metal-catalyzed hydrocarboxylation reactions. In this paper we report the ability of Ru(CO)3L2 (where L is a 2 e-donor) to catalyze the addition of variouscarboxylic acids onto terminal alkynes. A direct relationship between the regioselectivity of the product and the electronic property of the catalysis metal centre was observed.
