37559-18-5Relevant articles and documents
Evaluation of gem-Diacetates as Alternative Reagents for Enzymatic Regio-and Stereoselective Acylation of Alcohols
Koszelewski, Dominik,Brodzka, Anna,Madej, Arleta,Trzepizur, Damian,Ostaszewski, Ryszard
, p. 6331 - 6342 (2021/05/06)
Geminal diacetates have been used as sustainable acyl donors for enzymatic acylation of chiral and nonchiral alcohols. Especially, it was revealed that geminal diacetates showed higher reactivity than vinyl acetate for hydrolases that are sensitive to acetaldehyde. Under optimized conditions for enzymatic acylation, several synthetically relevant saturated and unsaturated acetates of various primary alcohols were obtained in very high yields up to 98% without E/Z isomerization of the double bond. Subsequently, the acyl donor was recreated from the resulting aldehyde and reused constantly in acylation. Therefore, the developed process is characterized by high atomic efficiency. Moreover, it was shown that acylation using geminal diacetates resulted in remarkable regioselectivity by discriminating among the primary and secondary hydroxyl groups in 1-phenyl-1,3-propanediol providing exclusively 3-acetoxy-1-phenyl-propan-1-ol in good yield. Further, enzymatic kinetic resolution (EKR) and chemoenzymatic dynamic kinetic resolution (DKR) protocols were developed using geminal diacetate as an acylating agent, resulting in chiral acetates in high yields up to 94% with enantiomeric excesses exceeding 99%.
Molybdenum-modified mesoporous SiO2as an efficient Lewis acid catalyst for the acetylation of alcohols
Hlatshwayo, Xolani S.,Ndolomingo, Matumuene Joe,Bingwa, Ndzondelelo,Meijboom, Reinout
, p. 16468 - 16477 (2021/05/19)
A suitable, expeditious and well-organized approach for the acetylation of alcohols with acetic anhydride in the presence of 5%MoO3-SiO2 as an optimum environmentally benign heterogeneous catalyst was developed. The high surface area obtained for 5%MoO3-SiO2, 101 m2 g-1 compared to other catalysts, 22, 23, and 44 m2 g-1 for 5%WO3-ZrO2, 5%WO3-SiO2, and 5%MoO3-ZrO2, respectively, appears to be the driving force for better catalytic activity. Amongst the two dopants used, molybdenum oxide is the better dopant compared to its tungsten oxide counterpart. High yields of up to 86% were obtained with MoO3 doping while WO3 containing catalysts did not show any activity. Other reaction parameters such as reactor stirring speed, and solvent variation were studied and revealed that the optimum stirring speed is 400 rpm and cyclohexane is the best solvent. Thus, the utilization of affordable and nontoxic materials, short reaction times, reusability, and producibility of excellent yields of the desired products are the advantages of this procedure.
Neighboring Carbonyl Group Assisted Hydration of Unsymmetrical Aryl Alkynes Overriding Regular Selectivity
Mendhekar, Kishor L.,Pradhan, Tapas R.,Mallampudi, N. Arjunreddy,Mohapatra, Debendra K.
, p. 5787 - 5797 (2019/08/21)
A mild and highly regioselective gold-catalyzed hydration of γ-acetoxy aryl alkynes leading to anti-Markovnikov products by the assistance of a neighboring carbonyl group is presented. The reaction procedure operates under room temperature conditions with
Gold-Catalyzed 1,2-Acyloxy Migration/Coupling Cascade of Propargyl Diazoacetates: Synthesis of Isomycin Derivatives
Bao, Ming,Wang, Xin,Qiu, Lihua,Hu, Wenhao,Hong Chan, Philip Wai,Xu, Xinfang
supporting information, (2019/03/19)
An efficient gold(I)-catalyzed carbocyclization reaction for the synthesis of isomycin derivatives from propargyl diazoacetates has been developed. The suggested cyclization pathway delineated the first example of a vinyl gold carbenoid species generated in situ from gold(I)-catalyzed 1,2-acyloxy migration and intercepted by a cross-coupling reaction with the remaining tethered diazo functionality. The use of protic additives was essential to regulating the reaction outcome by fine-tuning the catalytic preference of the gold(I) complex.
Site-Selective α-Alkoxyl Alkynation of Alkyl Esters Mediated by Boryl Radicals
Guo, Ao,Han, Jia-Bin,Zhu, Lei,Wei, Yin,Tang, Xiang-Ying
supporting information, p. 2927 - 2931 (2019/04/17)
A novel method for site-selective C-H functionalization of ethyl acetate mediated by pyridine-boryl radicals is presented, delivering a variety of 4-phenylbut-3-yn-2-yl acetate derivatives under mild conditions. A distinguishing feature of this reaction i
Harnessing Nucleophilicity of Allenol Ester with p-Quinone Methides via Gold Catalysis: Application to the Synthesis of Diarylmethine-Substituted Enones
Sharma, Brijesh M.,Rathod, Jayant,Gonnade, Rajesh G.,Kumar, Pradeep
, p. 9353 - 9363 (2018/06/29)
A gold(I)-catalyzed protocol for intermolecular 1,6-conjugate addition of nucleophilic allenol ester generated in situ through [3,3]-sigmatropic rearrangement with p-quinone methides (p-QMs) has been developed. The gold catalyst plays a dual role by the acid-triggered activation of alkynes and at the same time as a Lewis acid for activation of p-QMs toward nucleophilic attack. This method enables rapid access to a wide range of densely functionalized diarylmethine-substituted enones, a Morita-Baylis-Hillman (MBH) product with high selectivity, excellent yields, and broad substrate scope.
Electrochemical properties and reactions of organoboronic acid esters containing unsaturated bonds at their α-position
Ohtsuka, Kazuhiro,Inagi, Shinsuke,Fuchigami, Toshio
, p. G23 - G28 (2017/12/26)
Electrochemical analyses of 2-(cynnamyl)boronic acid pinacol ester and (3-phenyl-2-propynyl)boronic acid pinacol ester, and their trimethylsilyl analogues as well as their parent compounds were comparatively studied by cyclic voltammetry measurements. We
Selective acetylation of primary alcohols by ethyl acetate
Singha, Raju,Ray, Jayanta K.
, p. 5395 - 5398 (2016/11/11)
A KOtBu and ethyl acetate mediated efficient methodology has been developed for the acetylation of primary and secondary alcohols where ethyl acetate is the source of acetyl group. The reaction is fast, mild, efficient, and highly selective towards the primary alcohols.
Electrophile-Mediated Reactions of Functionalized Propargylic Substrates
Urbanaite, Aurelija,Jonu?is, Mantas,Buk?naitiene, Rita,Balkaitis, Simonas,?ikotiene, Inga
, p. 7091 - 7113 (2015/11/16)
Metal-free halogen, chalcogen, or oxocarbenium ion mediated yne-carbonyl or yne-thioxo transformations of a range of N- and O-propargylic compounds have been studied. This investigation has led to the development of a mild, economic, and effective method for the synthesis of functionalized 4H-1,3-oxazines, 4H-1,3-thiazines, 4,5-dihydrothiazoles, and α-substituted enones. The structure of the propargylic substrate and the nature of electrophile influence both the outcome and regioselectivity of processes. Metal-free electrophile-mediated transformations of various N- and O-propargylic compounds have been studied. The scope and limitations of these reactions have been evaluated by using a broad range of substrates.
Synthesis of α-acyloxyketone derivatives via the platinum-catalyzed migration of propargylic esters
Tsukano, Chihiro,Yamamoto, Sho,Takemoto, Yoshiji
, p. 710 - 719 (2015/11/27)
The synthesis of α-acyloxyketones via the migration of a propargylic ester followed by the intramolecular nucleophilic addition of the resulting allene was achieved using a cationic platinum catalyst. The optimized conditions for this transformation were
