3842-03-3Relevant articles and documents
Formation of Acetals and Ketals from Carbonyl Compounds: A New and Highly Efficient Method Inspired by Cationic Palladium
Green, Shawn D.,Kindoll, Tyler,Lazaro-Martinez, Brenda,Mensah, Enoch A.,West, Jesse
, p. 1810 - 1814 (2019/09/09)
The development of a new, highly efficient, and simple method for masking carbonyl groups as acetals and ketals is described. This methodology relies on the nature of the palladium catalyst to direct the acetalization/ketalization reaction. This new protocol is mild and proceed with a very low catalyst loading at ambient temperatures. The method has been extended to a wide variety of different carbonyl compounds with various steric encumbrances to form the corresponding acetals and ketals in excellent yields.
A Stereoselective Reductive Hosomi-Sakurai Reaction
Bauer, Adriano,Maulide, Nuno
supporting information, p. 1461 - 1464 (2018/03/09)
A novel reductive variant of the classical Hosomi-Sakurai reaction is reported. This transformation hinges on a redox-neutral, stereoselective internal reduction event under mild conditions. This operationally simple reaction relies on readily available starting materials and leads to useful products in diastereoselectivities of up to 7:1. The versatility of this new method is demonstrated through the stereoselective one-step synthesis of an AChE inhibitor.
Acetals: A new organocatalysis chemotype for one-pot enantioselective α-amination
Msutu, Ath'Enkosi,Hunter, Roger
supporting information, p. 2295 - 2298 (2014/04/17)
Conditions are described for one-pot Br?nsted acid and organocatalysed enantioselective α-amination of acetals and associated functionalities. Of the organocatalysts screened, proline tetrazole gave the highest ee, while aqueous monochloroacetic acid proved to be the best Br?nsted acid activator regarding minimizing racemization and maximizing product yield. The reaction opens up the way for using masked carbonyl functionalities in organocatalysis.
Characterization of aroma compounds of Chinese "Wuliangye" and "Jiannanchun" liquors by aroma extract dilution analysis
Fan, Wenlai,Qian, Michael C.
, p. 2695 - 2704 (2007/10/03)
Aroma compounds in Chinese "Wuliangye" liquor were identified by gas chromatography-olfactometry (GC-O) after fractionation. A total of 132 odorants were detected by GC-O in Wuliangye liquor on DB-wax and DB-5 columns. Of these, 126 aromas were identified by GC-mass spectrometry (MS). Aroma extract dilution analysis (AEDA) was further employed to identify the most important aroma compounds in "Wuliangye" and "Jiannanchun" liquors. The results showed that esters could be the most important class, especially ethyl esters. Various alcohols, aldehydes, acetals, alkylpyrazines, furan derivatives, lactones, and sulfur-containing and phenolic compounds were also found to be important. On the basis of flavor dilution (FD) values, the most important aroma compounds in Wuliangye and Jiannanchun liquors could be ethyl butanoate, ethyl pentanoate, ethyl hexanoate, ethyl octanoate, butyl hexanoate, ethyl 3-methylbutanoate, hexanoic acid, and 1,1-diethoxy-3-methylbutane (FD ≥ 1024). These compounds contributed to fruity, floral, and apple- and pineapple-like aromas with the exception of hexanoic acid, which imparts a sweaty note. Several pyrazines, including 2,5-dimethyl-3-ethylpyrazine, 2-ethyl-6-methylpyrazine, 2,6-dimethylpyrazine, 2,3,5-tri-methylpyrazine, and 3,5-dimethyl-2-pentylpyrazine, were identified in these two liquors. Although further quantitative analysis is required, it seems that most of these pyrazine compounds had higher FD values in Wuliangye than in Jiannanchun liquor, thus imparting stronger nutty, baked, and roasted notes in Wuliangye liquor.
Bronsted acidic ionic liquids as efficient and recyclable catalysts for protection of carbonyls to acetals and ketals under mild conditions
Du, Yuying,Tian, Fuli
, p. 2703 - 2708 (2007/10/03)
A series of acidic ionic liquids have been used as efficient catalysts for the protection of various carbonyl compounds at room temperature. The features of mild conditions, satisfactory isolated yield, simple workup, and the recyclability of the catalyst were present in this process. Copyright Taylor & Francis, Inc.
Sulfamic acid as a cost-effective and recyclable catalyst for protection of carbonyls to acetals and ketals under mild conditions
Gong, Weizhong,Wang, Bo,Gu, Yanglong,Yan, Liang,Yang, Liming,Suo, Jishuan
, p. 4243 - 4247 (2007/10/03)
An efficient H2NSO3H-catalyzed protection of various carbonyl compounds at room temperature was investigated. The features of mild conditions, cost-efficient catalyst, simple workup, and the recyclability of the catalyst were represented in this process.
Reactions of trialkylalanes with cyclic acetals and orthoformates in CH2Cl2 and ClCH2CH2Cl as solvents
Gafarova,Dekhtyar',Dekhtyar',Fatykhov,Spirikhin,Vostrikova,Zlotskii,Dokichev
, p. 1003 - 1008 (2007/10/03)
Under mild conditions, trialkylalanes (Et3Al and Bu i3Al) in chlorine-containing solvents (CH 2Cl2 or ClCH2CH2Cl) react with cyclic acetals and orthoformates to form glycol monoethers and dialkylacetals, respectively, in high yields. The 1H NMR spectroscopic data demonstrate that CH2Cl2 or ClCH2CH 2Cl interacts with Bui3Al.
Method for producing enol ethers
-
, (2008/06/13)
Enol ethers of the formula I where R1is an aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic radical which may carry further substituents which do not react with acetylenes or allenes, and the radicals R, independently of one another, are hydrogen or aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic radicals, which may be bonded to one another to form a ring, and m is 0 or 1, are prepared by reacting an acetal or ketal of the formula II with an acetylene or allene of the formula III or IV where R and R1have the abovementioned meanings, in the gas phase at elevated temperatures in the presence of a zinc- or cadmium- and silicon- and oxygen-containing heterogeneous catalyst.
