- Base-Catalyzed Borylation/B-O Elimination of Propynols and B2pin2 Delivering Tetrasubstituted Alkenylboronates
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An efficient approach to tetrasubstituted alkenylboronates via a cascade borylation/B-O elimination of propynols and B2pin2 was disclosed. A series of tetrasubstituted alkenylboronates were readily furnished with this strategy in good yields, with further transformations leading to tetrasubstituted alkenes and β-diketones demonstrating the synthetic potential of the alkenylboronates constructed by this strategy as versatile intermediates in organic synthesis.
- Kuang, Zhijie,Chen, Haohua,Yan, Jianxiang,Yang, Kai,Lan, Yu,Song, Qiuling
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- Method for the combined production of tetramethyldecyndiol and dimethylhexynyl alcohol
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A method for co-producing tetramethyldecyndiol and dimethylhexynyl alcohol, using 4-methyl-2-pentanone and acetylene as raw material, potassium hydroxide as a catalyst, and organic solvent as a dispersant, first reacting 4-methyl-2-pentanone with acetylene at atmospheric pressure or low pressure at a lower temperature to form a dimethylhexynyl alcohol-potassium hydroxide complex, and then mixing it with 4-methyl-2-pentanone quickly reacts through a high-temperature reaction tube to generate tetramethyldyne glycol. After the reaction product is water-relieved of potassium hydroxide, each target product is collected by fractionation. The present invention has the characteristics of short reaction time, low catalyst consumption and easy recovery of products.
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Paragraph 0025-0040
(2022/01/12)
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- Method for efficiently preparing alkynol
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The invention relates to a method for efficiently preparing alkynol, belongs to the field of preparation of chemical intermediates and chemicals, and particularly relates to a preparation method of alkynol. The preparation method comprises the following steps that 1, alkali metal is added into an anhydrous alcohols solvent; an alcohol-alkali metal solution is prepared; 2, a compound I is added into the alcohol-alkali metal solution; uniform stirring is performed; cooling is performed to be 0 DEG C or below; 3, acetylene is introduced through being metered at normal pressure; alkynol is obtained; 4, the alkynol solution after reaction is neutralized by ammonium chloride and a same alcohol mixed suspension system; 5, the neutralized mixed suspension system is filtered; after alcohols are recovered from filter liquid, reduced pressure distillation is performed to obtain an alkynol product. The method overcomes the defect that under the existing harsh reaction conditions of high pressure,liquid ammonia and the like, the solid potassium hydroxide feeding difficulty is avoided; under the ordinary pressure condition, the ketone compounds are converted into alkynol at high conversion rate. The method has the advantages of high conversion rate, simple process and good product purity.
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Paragraph 0036; 0037; 0038; 0043; 0044; 0045; 0046
(2018/12/14)
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- Alkynylation of aldehydes and ketones using the Bu4NOH/H 2O/DMSO catalytic composition: A wide-scope methodology
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The Favorsky reaction of a wide range of aldehydes and ketones with alkynes has been implemented under mild conditions (5-20 C). Using a Bu 4NOH/H2O/DMSO catalytic system, propargylic alcohols are formed cleanly in 39-93% (mostly 72-93%) yields and with ca. 100% selectivity. The method is suitable for aliphatic, aromatic, and heteroaromatic aldehydes and ketones, and for aliphatic, aromatic, and functionalized acetylenes. Thus, this represents the most general and efficient protocol to achieve the Favorsky reaction. Copyright
- Schmidt, Elena Yu.,Cherimichkina, Natalia A.,Bidusenko, Ivan A.,Protzuk, Nadezhda I.,Trofimov, Boris A.
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p. 4663 - 4670
(2014/08/05)
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- Pd(II)-catalyzed highly regio-and stereoselective assembly of C-C double bonds: An efficient method for the synthesis of 2,4-dihalo-1,3,5-trienes from alkynols
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A highly efficient method for the synthesis of 2,4-dihalo-1,3,5-trienes from alkynols was developed. This chemistry allows access to multiple conjugated double bonds in a single step with high stereoselectivity.
- Jiang, Huanfeng,Gao, Yang,Wu, Wanqing,Huang, Yubing
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supporting information
p. 238 - 241
(2013/03/13)
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- Gold-catalyzed regioselective hydration of propargyl acetates assisted by a neighboring carbonyl group: Access to α-acyloxy methyl ketones and synthesis of (±)-actinopolymorphol B
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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.
- Ghosh, Nayan,Nayak, Sanatan,Sahoo, Akhila K.
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p. 500 - 511
(2011/04/17)
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- Construction of highly substituted stereodefined dienes by cross-coupling of α-allenic acetates
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The assembly of highly substituted dienes remains a challenge for organic chemistry. This work represents a strategy for the construction of highly substituted 1,3-dienes by means of a Tsuji-Trost cross coupling between α-allenic acetates and organozinc reagents. The reaction is high yielding, and installs a trisubstituted olefin with E/Z selectivities up to 95:5 favoring the (E) product. A cheap, commercially available palladium precatalyst and a ligand are used to control the E/Z selectivity. Furthermore, an interesting reversal in selectivity is noted in which appropriate choice of ligand may be used to control the outcome of the reaction and favor the (Z) product. Thirteen examples are described, highlighting the substrate scope of the reaction. It is hoped that the straight-forward reaction conditions and high selectivity will make this reaction of broad use in natural product chemistry. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Schneekloth Jr., John S.,Pucheault, Mathieu,Crews, Craig M.
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- AN EFFICIENT AND QUICK LABORATORY SCALE METHOD FOR THE ETHYNYLATION OF SOME ALIPHATIC AND CYCLOALIPHATIC CARBONYL COMPOUNDS.
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A number of aliphatic and cycloaliphatic carbonyl compounds have been ethynylated in tetrahydrofuran at atmospheric pressure using uncomplexed potassium tert-butoxide as a catalyst.
- Verkruijsse, Hermann D.,Graaf, Wim de,Brandsma, Lambert
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p. 131 - 134
(2007/10/02)
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