52789-73-8Relevant academic research and scientific papers
A heterogeneous gold(I)-catalyzed regioselective hydration of propargyl acetates toward α-acyloxy methyl ketones
Cai, Mingzhong,Du, Yingying,Yao, Fang,Zhang, Rongli
, (2020/02/04)
A heterogeneous gold(I)-catalyzed regioselective hydration of propargyl acetates has been developed that proceeds smoothly in 1,4-dioxane at room temperature in the presence of 1 mol% diphenylphosphine-modified MCM-41-anchored gold(I) complex [Ph2P-MCM-41-AuSbF6] as catalyst and provides an efficient and practical approach for the synthesis of a variety of α-acyloxy methyl ketones with high atom economy, good to excellent yield, and high functional group tolerance. This new immobilized gold(I) catalyst can readily be obtained by a simple preparative procedure from commercially available reagents, and recovered via a filtration process and reused at least seven times without apparent loss of activity.
"Silver effect" in gold(I) catalysis: An overlooked important factor
Wang, Dawei,Cai, Rong,Sharma, Sripadh,Jirak, James,Thummanapelli, Sravan K.,Akhmedov, Novruz G.,Zhang, Hui,Liu, Xingbo,Petersen, Jeffrey L.,Shi, Xiaodong
supporting information; experimental part, p. 9012 - 9019 (2012/07/02)
Clear experimental evidence from X-ray photoelectron spectroscopy and 31P NMR spectroscopy has been obtained for the first time to confirm that the combination of Ag+ cation with [L-Au]+ results in the formation of different complexes in solution. Re-evaluation of literature-reported gold-catalyzed reactions revealed a significant difference in the reactivities with and without silver. In extreme cases (more than "rare"), the conventional [L-Au]+ catalysts could not promote the reaction without the presence of silver. This investigation has therefore revealed a long-overlooked "silver effect" in gold catalysis and should lead to revision of the actual mechanism.
Gold-catalyzed regioselective hydration of propargyl acetates assisted by a neighboring carbonyl group: Access to α-acyloxy methyl ketones and synthesis of (±)-actinopolymorphol B
Ghosh, Nayan,Nayak, Sanatan,Sahoo, Akhila K.
, p. 500 - 511 (2011/04/17)
A general atom-economical approach for the synthesis of α-acyloxy methyl ketone is demonstrated through regioselective hydration of a wide range of propargyl acetates. Readily available catalyst comprising of 1% Ph 3PAuCl and 1% AgSbF6 in dioxane-H2O efficiently hydrolyzes the terminal alkynes of the propargyl acetate in the absence of acid promoters at ambient temperature within a short time. Effective regioselective hydration is facilitated by the neighboring carbonyl group as demonstrated through 18O-labeling study. Compatibility of functional moieties and tolerance to various acid-labile protecting groups are observed. The catalytic condition is also suitable to perform hydration of TMS-substituted propargyl acetates, even though it requires prolonged reaction time for completion. Stereointegrity of the propargylic acetate is preserved during the hydration. The robustness of the system is successfully demonstrated through gram scale preparation of the product in nearly quantitative yield. The common α-acyloxy methyl ketone is transformed to 1,2-diol and 1,2-amino alcohol derivatives. Synthesis of actinopolymorphol B is achieved for the first time involving hydration of the propargyl acetate as the key step.
Conversion of propargylic alcohols to β-oxo esters catalyzed by novel ruthenium-phosphoramidite complexes
Costin, Stephen,Rath, Nigam P.,Bauer, Eike B.
supporting information; experimental part, p. 2414 - 2424 (2009/11/30)
A series of half-sandwich phosphoramidite complexes of ruthenium were synthesized and employed as catalysts in the atom-economical formation of β-oxo esters from carboxylic acids and propargylic alcohols. Reaction of the phosphoramidites (R)-BINOL-PNR2 (R=Me, 1a; i-Pr, 1b; benzyl, 1c) and (rac)-6,6′-dibromo-BINOL-PNMe2 (1d) with the dimeric p-cymene-ruthenium dichloride complex, [RuCl2(p-cymene)]2, gave the complexes [RuCl2(p-cymene)(L)] (L=1a, 7a; 1b, 7b; 1c, 7c; 1d, 7d) in 96-66% yield. Accordingly, reaction of (R)-BINOL(8H)-PNMe2 (2a) and (R)-BINOL(8H)-PN-(benzyl)2 (2b) with [RuCl2(p-cymene)] 2 afforded the complexes [RuCl2(p-cymene)(L)] (L=2a, 8a; 2b, 8b) in 82% and 86% yield. In a similar reaction, treatment of (R)-BIPHEN-PNMe2 (9) with [RuCl2(p-cymene)] 2 gave the complex [RuCl2(p-cymene)(9)] (11) in 60% yield. Finally, phosphoramidite 1b reacted with [RuCl2(C6Me 6)]2 to give [RuCl2(C6Me 6)(1b)] (12) in 78% yield. All novel complexes are catalytically active in the formation of β-oxo esters from propargylic alcohols and carboxylic acids. Standard conditions involve cyclohexane solvent, propargylic alcohol (1.0 equiv.), carboxylic acid (1.0 equiv.), ruthenium catalyst (1.5 mol%), and 90°C for 5-18 h. Isolated yields of the β-oxo esters range from 87 to 16% and show broad substrate generality. The reaction proceeds without racemization if a chiral propargylic alcohol is employed. The method is practical as no additives are required and the exclusion of oxygen and moisture is not needed. Complex 7c turned out to be the most effective catalyst (5 h reaction time), showing that the ligand structure has a profound impact on the catalytic performance. The crystal structure of 7a was determined, confirming an octahedral coordination geometry about the ruthenium center.
Palladium(II)-catalyzed oxidative rearrangement of propargyl esters
Kataoka,Watanabe,Goto
, p. 4181 - 4184 (2007/10/02)
Propargyl esters were converted to α-acyloxy-α,β-unsaturated aldehydes by palladium (II) catalysts under oxygen atmosphere in good to excellent yields.
Ruthenium-Catalyzed Selective Addition of Carboxylic Acids to Alkynes.A Novel Synthesis of Enol Esters
Mitsudo, Take-aki,Hori, Yoji,Yamakawa, Yasushi,Watanabe, Yoshihisa
, p. 2230 - 2239 (2007/10/02)
Carboxylic acids react with alkynes in the presence of a catalytic amount of bis(ν5-cyclooctadienyl)ruthenium/trialkylphosphine/maleic anhydride in toluene at 60-80 deg.C to give enol esters having a terminal methylene group in good to excellent yields with high regioselectivity.The deuterium distributions in the products of the reaction of acetic acid-d with 1-hexyne and ethyl propargyl carbonate were examined.Kinetic measurments revealed that the rate has first-order dependence on carboxylic acid, alkyne, and the initial concentration of the ruthenium catalyst.
NOVEL OXIDIZING PROPERTIES OF p-METHOXYBENZENETELLURINIC ACID ANHYDRIDE
Hu, Nan Xing,Aso, Yoshio,Otsubo, Tetsuo,Ogura, Fumio
, p. 6099 - 6102 (2007/10/02)
The title compound has proved to be a mild oxidizing agent like the corresponding telluroxide or tellurone towards thiol, phosphine, thioamide, thiourea, thionoester, and benzylic alcohol.In addition, it serves as a selective catalyst for the hydration of terminal alkyne.
Alkyl esters of 1-alkanoyl cycloalkanols and organoleptic uses thereof
-
, (2008/06/13)
Described is a process for preparing several substituted or unsubstituted cycloalkyl acyl alkanoates defined according to the generic structure: STR1 wherein R1 and R2 taken together complete a cycloalkyl moiety or methyl, dimethyl or trimethyl substituted cycloalkyl moiety containing five or six carbon atoms in the ring and wherein R3 is C1 -C3 lower alkyl and R4 is methyl or hydrogen by reacting a compound having the generic structure: STR2 in an aqueous silver-ion containing solution having a weakly acidic pH at elevated temperatures. The compounds so produced are useful for their organoleptic properties in consumable materials, such as foodstuffs, foodstuff flavorants, chewing gums, chewing gum flavorants, toothpastes, toothpaste flavorants, medicinal products, medicinal product flavorants, chewing tobaccos, chewing tobacco flavorants, smoking tobaccos, smoking tobacco flavorants, perfume compositions, perfumed articles, such as cationic, anionic, nonionic and zwitterionic detergents, fabric softener compositions, drier-added fabric softener articles, textile sizing agents and optical brighteners for textiles as well as colognes.
