- The role of potassium cation in the Favorskii ethynylation of acetone: Effekt of dibenzo-18-crown-6
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Macrocyclic polyether dibenzo-18-crown-6 possessing a specific affinity for potassium cation inhibits ethynylation of acetone with acetylene in the presence of KOH according to Favorskii. The inhibition becomes stronger in the presence of the complex dibenzo-18-crown-6·KOH·MeOH as catalyst (both in excess acetone and in DMSO). The effect does not originate from deactivation of acetone, for its aldol-like condensation is accelerated in the presence of both dibenzo-18-crown-6 and its complex (the selectivity of ethynylation sharply falls down). Thus, apart from the high basicity of the medium, activation of acetylene due to complex formation with potassium cation plays an important role in the Favorskii ethynylation of ketones.
- Trofimov,Nosyreva,Mal'kina
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Read Online
- Modified copolymers of bifunctional vinyl ethers with methyl vinyl sulfide as active matrices of solid superbases
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Reactive linear and crosslinked copolymers of diethylene glycol divinyl ether and ethylene glycol vinyl glycidyl ether with methyl vinyl sulfide have been synthesized in the presence of 2,2′-azobis(isobutyronitrile) (2%, 60 °C, 45-55 h) in ～53% yield. The hydrolyzed at the residual vinyloxy and epoxy groups and oxidized at the methylthio groups copolymers upon treatment with KOH afford alkoxide (complex) and crown-like superbases. They are capable of catalyzing the acetone ethynylation, as well as the prototropic isomerization of methyl propargyl ether to allenyl methyl ether and vinylation of ethylene and diethylene glycols with acetylene.
- Trofimov,Morozova,Mikhaleva,Markova,Tatarinova,Henkelmann
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Read Online
- Enantio- And Diastereodivergent Construction of 1,3-Nonadjacent Stereocenters Bearing Axial and Central Chirality through Synergistic Pd/Cu Catalysis
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In contrast to the widely explored methods for the asymmetric synthesis of molecules bearing a single stereocenter or adjacent stereocenters, the concurrent construction of 1,3-stereogenic centers in an enantio- and diastereoselective manner remains a challenge, especially in acyclic systems. Herein, we report an enantio- and diastereodivergent construction of 1,3-nonadjacent stereocenters bearing allenyl axial and central chirality through synergistic Pd/Cu-catalyzed dynamic kinetic asymmetric allenylation with racemic allenylic esters. The protocol is suitable for a wide range of substrates including the challenging allenylic esters with less sterically bulky substituents and provided chiral allenylic products bearing 1,3-nonadjacent stereocenters with high levels of enantio- and diastereoselectivities (up to >20:1 dr and >99% ee). Furthermore, several representative transformations involving axial-to-central chirality transfer were conducted, affording useful structural motifs containing nonadjacent stereocenters in a diastereodivergent manner.
- Huo, Xiaohong,Ma, Shengming,Xiao, Junzhe,Zhang, Jiacheng,Zhang, Wanbin,Zhao, Ling
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supporting information
p. 12622 - 12632
(2021/08/31)
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- Separation method of 2-methyl-3-butyn-2-ol
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The invention belongs to the technical field of acetylene alcohol production, and particularly relates to a separation method of 2-methyl-3-butyn-2-ol, which comprises the following steps: pretreatinga reaction solution containing 2-methyl-3-butyn-2-ol to remove unreacted acetone and contained salt from the reaction solution to obtain a 2-methyl-3-butyn-2-ol crude product, with the content of 2,5-dimethyl-3-hexyn-2,5-diol in the reaction solution containing 2-methyl-3-butyn-2-ol being not higher than 0.1 wt%; separating and purifying the 2-methyl-3-butyn-2-ol crude product by virtue of membrane separation treatment and reduced pressure distillation treatment, so as to obtain a 2-methyl-3-butyn-2-ol product. According to the method disclosed by the invention, water in the product can be removed and the content of the 2,5-dimethyl-3-hexyn-2,5-diol can be reduced under the condition that the investment and the energy consumption are reduced, so that the 2-methyl-3-butyn-2-ol with relatively high purity and conversion rate is obtained.
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Paragraph 0082-0093; 0158-0160
(2020/11/01)
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- Synthetic method of 3-methoxy-3-methylbutyne
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The invention discloses a synthetic method of 3-methoxy-3-methylbutyne. The method comprises the following steps: using acetone and acetylene as starting raw materials, firstly synthesizing 3-methylbutyn-3-ol, and performing a reaction on the 3-methylbutyn-3-ol and dimethyl sulfate to obtain the 3-methoxy-3-methylbutyne. According to the synthetic method of the 3-methoxy-3-methylbutyne provided bythe invention, the raw materials used in the synthetic method have a low price and low costs and are easy to obtain, the synthetic method has a short synthetic route, a high yield, and high chemicalpurity of the obtained product, no special production equipment is needed in all reactions, and the obtained intermediate and the final product do not need to be treated by column chromatography and crystallization purification.
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Paragraph 0012-0020
(2019/11/28)
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- 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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supporting information
p. 5153 - 5157
(2018/09/12)
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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; 0039; 0040; 0041; 0042
(2018/12/14)
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- Convenient and highly efficient routes to 2 H-chromene and 4-chromanone derivatives: Iodine-promoted and p-toluenesulfonic acid catalyzed cascade cyclizations of propynols
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A convenient strategy is presented for the easy preparation of a series of 2 H-chromenes under mild conditions through iodocyclization of readily accessible propynols. In addition, various 4-chromanones can be synthesized through a p-toluenesulfonic acid catalyzed cascade cyclization with high efficiency (yields up to 99%). Our developed reaction systems are proven to have good functional-group applicability and can be scaled up to gram quantities in satisfactory yields. These systems also provide a new synthetic strategy for two types of important flavonoid skeleton without using costly and toxic metal catalysts. Additionally, the resulting halides could be further exploited in subsequent palladium-catalyzed coupling reactions, so these compounds could act as potential intermediates for the construction of some valuable drug molecules.
- Qiu, Yi-Feng,Ye, Yu-Ying,Song, Xian-Rong,Zhu, Xin-Yu,Yang, Fang,Song, Bo,Wang, Jia,Hua, Hui-Liang,He, Yu-Tao,Han, Ya-Ping,Liu, Xue-Yuan,Liang, Yong-Min
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supporting information
p. 3480 - 3487
(2015/03/04)
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- Gold-catalyzed reactions of propargylic esters with vinylazides for the synthesis of Z- or E-configured buta-1,3-dien-2-yl esters
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Gold-catalyzed synthesis of buta-1,3-dien-2-yl esters by the reaction of propargyl esters with vinylazides is described; the reaction mechanism is postulated to involve a vinyl attack of vinylazides at alkenyl gold carbenes.
- Wagh, Sachin Bhausaheb,Liu, Rai-Shung
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supporting information
p. 15462 - 15464
(2015/10/20)
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- Efficient synthesis and antibacterial activities of some novel 1,2,3-triazoles prepared from propargylic alcohols and benzyl azides
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A simple and effective procedure for regioselective preparation of 1,2,3-triazoles from benzyl azides and propargylic alcohols is described using CuSO4·5H2O and sodium ascorbate. To screen the antibacterial activity of some newly synthesized triazole derivatives, minimum inhibitory concentration of 3d and 3k was evaluated against gram positive Staphylococcus aureus and Bacillus subtilis and gram negative Escherichia coli and Pseudomonas aeruginosa.
- Hosseinzadeh, Rahman,Abolfazli, Mohammadreza Khadem,Mohseni, Mojtaba,Mohadjerani, Maryam,Lasemi, Zahra
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p. 1298 - 1305
(2015/04/27)
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- Diastereo- and enantioselective propargylation of benzofuranones catalyzed by pybox-copper complex
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Diastereo- and enantioselective preparation of 2,2-disubstituted benzofuran-3(2H)-one has been realized by a pybox-copper catalyzed reaction between 2-substituted benzofuran-3(2H)-one and propargyl acetate. The utility of this method was demonstrated by further transformation of the terminal alkyne into a methyl ketone without loss of enantiomeric purity.
- Zhao, Long,Huang, Guanxin,Guo, Beibei,Xu, Lijun,Chen, Jie,Cao, Weiguo,Zhao, Gang,Wu, Xiaoyu
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supporting information
p. 5584 - 5587
(2015/02/19)
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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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- Facile synthesis of halogenated spiroketals via a tandem iodocyclization
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A strategy for the synthesis of spiroketal compounds through a tandem iodocyclization of 1-(2-ethynylphenyl)-4-hydroxybut-2-yn-1-one derivatives is presented. This reaction could proceed under very mild conditions in a short time and avoid the use of expensive and toxic metal catalysts. Moreover, the resulting halides can be further exploited by subsequent palladium-catalyzed coupling reactions, which act as the important intermediates for building other valuable compounds.
- Wang, Jia,Zhu, Hai-Tao,Li, Ying-Xiu,Wang, Li-Jing,Qiu, Yi-Feng,Qiu, Zi-Hang,Zhong, Mei-Jin,Liu, Xue-Yuan,Liang, Yong-Min
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supporting information
p. 2236 - 2239
(2014/05/06)
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- PROCESS FOR THE PRODUCTION OF 2-ALKYL-3-BUTYN-2-OLS
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The present invention relates to an improved process for the production of 2-alkyl-3-butin-2-ols; especially to a new purification step.
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Page/Page column 7; 9
(2014/08/07)
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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(I)-catalysed alkene cycloaddition reactions of propargyl acetals
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Studies on gold(I)-catalysed reactions of propargyl acetals are scarce, unlike those of the corresponding esters. We have investigated gold(I)-catalysed cyclization reactions of both propargyl acetals and esters in order to identify the abilities of the t
- Iqbal, Naseem,Sperger, Christian A.,Fiksdahl, Anne
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supporting information
p. 907 - 914
(2013/03/14)
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- A novel Ireland-Claisen rearrangement/Diels-Alder tandem reaction of propargylic acrylates with acyclic dienophiles
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A novel DABCO-catalyzed Ireland-Claisen rearrangement/Diels-Alder tandem reaction of propargylic acrylates 3 with dienophiles 4 was developed in the presence of an excess TMSCl and DBU with 1% hydroquinone as polymerization inhibitor in acetonitrile at refluxing temperature under air. This protocol gave cyclic α,β-unsaturated carboxylic acids 5 with complete regioselectivity.
- Li, Yun-Xia,Sheng, Yi-Lin,Zhang, Bi-Song
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p. 137 - 139
(2013/06/26)
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- N-(phenylselenomethyl)phthalimide as new reagent for mild protection of alcohols as Pim-ethers
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A mild activation of N-(phenylselenomethyl)phthalimide by iodonium ion in the presence of alcohols to give the corresponding O-phthalimidomethyl derivatives (Pim-ethers) is provided. Simple cleavage of the phthalimido group with ethylenediamine is also reported thus making this approach a new and efficient method of protecting alcohols.
- Temperini, Andrea,Minuti, Lucio
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scheme or table
p. 2709 - 2711
(2012/07/16)
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- Stereoselective One-Pot synthesis of 1-Aminoindanes and 5,6-Fused azacycles using a Gold-Catalyzed Redox-Pinacol-Mannich-Michael cascade
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"Chemical Equation Presented" Just another Mannich Monday: A cascade intramolecular redox-pinacol-Mannich-Michael reaction sequence catalyzed by gold complexes can be used to generate a variety of structures including spirocycles, 1-aminoindanes, and 5,6-fused azabicycles that have a quaternary carbon center. The reaction is characterized by complete atom-economy, high diastereoselectivity, and remarkable efficiency through tandem reactions.
- Yeom, Hyun-Suk,Lee, Youngun,Jeong, Jaewon,So, Eunsoo,Hwang, Soojin,Lee, Ji-Eun,Lee, Shim Sung,Shin, Seunghoon
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supporting information; experimental part
p. 1611 - 1614
(2010/06/15)
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- Synthesis of annulated oxazolidinones as potential precursors of cyclic cis-β-amino alcohols
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A simple method for the synthesis of annulated 1,3-oxazolidin-2-ones from accessible ketones, acetylene, and carbon dioxide was developed. If their molecules contain arylalkyl substituents, intramolecular cyclization in acidic media gave rise to fused heterocyclic systems in high yields. The effects of the substituents in positions 3 and 5 of the oxazolidine ring on the regioselectivity of this cyclization were studied. The possibilities of converting oxazolidinones into cyclic cis-β-amino alcohols were studied.
- Chudinov,Gashev,Chernysheva,Semenov
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p. 123 - 136
(2007/10/03)
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- METHOD FOR THE PRODUCTION OF ACETYLENE ALCOHOLS
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The invention relates to a method for producing acetylene alcohols of general formula (I), wherein R1, R2 can independently be identical or different and represent optionally substituted hydrogen, an optionally substituted saturated, monounsaturated or polyunsaturated C1-C30 alkyl radical, aryl radical, cycloalkylalkyl radical, or cycloalkyl radical, or a group of general formula (II), wherein R3, R4 can independently be identical or different and represent optionally substituted hydrogen or an optionally substituted saturated, monounsaturated, or polyunsaturated C1-C30 alkyl radical, aryl radical, cycloalkylalkyl radical, or cycloalkyl radical while the dashed line can represent an additional double bond. Said acetylene alcohols are produced by monoethynylating a ketone of general formula R1-CO-R2 by (a) reacting lithium with a C1-C10 alkyl halide, (b) introducing acetylene gas, and (c) adding the ketone.
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Page/Page column 5-6
(2008/06/13)
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- METHOD FOR PREPARING ACETYLENE ALCOHOLS AND THEIR SECONDARY PRODUCTS
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A process for preparing at least one unsaturated alcohol (B) comprises the steps (I) to (III) below: (I) reaction of at least one alkali metal hydroxide or alkaline earth metal hydroxide with at least one alcohol (A) in at least one organic solvent (L) to give a mixture (G-I) comprising at least the alcohol (A), the solvent (L) and an alkoxide (AL); (II) reaction of at least one carbonyl compound of the formula R-CO-R' with at least one alkyne of the formula R''-C≡C-H and the mixture (G-I) obtained in step (I) to give a mixture (G-II) comprising at least the alcohol (A), the solvent (L) and an unsaturated alcohol (B); (III) distillation of the mixture (G-II) obtained in step (II) to give the alcohol or alcohols (B) and a mixture (G-III) comprising the solvent (L) and the alcohol (A), wherein the solvent (L) obtained in step (III) and the alcohol (A) obtained in step (III) are recycled as a mixture to step (I).
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Page/Page column 13
(2008/06/13)
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- PMHS-mediated couplings of alkynes or benzothiazoles with various electrophiles: Application to the synthesis of (-)-akolactone A
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Polymethylhydrosiloxane (PMHS) in combination with CsF facilitates the cross-coupling of alkynes or benzothiazoles with an array of vinyl, styryl, and aryl halides or nonaflates as well as acid chlorides. Experimental and spectroscopic evidence indicates that these reactions involve the in situ generation of a siloxyl intermediate. These cross-couplings proceed relatively quickly at room temperature and under amine-free conditions. To demonstrate the applicability of the method, a total synthesis of the cyctotoxic butanolide (-)-akolactone A was carried out.
- Gallagher, William P.,Maleczka Jr., Robert E.
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p. 6775 - 6779
(2007/10/03)
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- Preparation of alkynediols
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The process for preparing alkynediols of the formula (I) R1R2C(OH)—C≡C—C(OH)R1R2??(I) where R1, R2are each independently H, or a C1-20-hydrocarbon radical which may be substituted by one or more C1-6-alkyls and/or be interrupted by nonadjacent heteroatoms and/or contain C—C double or triple bonds, by reacting compounds of the formula (II) R1—C(═O)—R2??(II) with acetylene in a polar aprotic solvent is carried out in the presence of basic alkali metal salts as catalysts.
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Page column 3
(2010/11/29)
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- Preparation of higher alpha, beta-unsaturated alcohols
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Higher α,β-unsaturated alcohols are prepared by monoethynylation of a ketone by the NH3/KOH method, if desired hydrogenation of the acetylene alcohol in the presence of hydrogen over a Pd-containing thin layer catalyst, purifying distillation of the hydrogenation product, preferably in a dividing wall column with recirculation of the unreacted ketone to the ethynylation step, and, if desired, preparation of higher alcohols having in each case 5 more carbon atoms in the chain by reacting the alcohols prepared by monoethynylation and, if desired, partial hydrogenation with alkyl acetoacetatesor diketene in a Carroll reaction to form ketones and using these as starting materials for the steps ethynylation, optional hydrogenation and fractional distillation.
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- Carbon-carbon bond formation in regio- and stereoselective palladium-catalyzed cyclization of allene-substituted conjugated dienes
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Regio- and stereoselective palladium-catalyzed reactions of allene-substituted 1,3-dienes 1 in acetic acid at room temperature lead to cyclization with formation of a carbon-carbon bond between the middle carbon of the allene and the terminal carbon of the 1,3-diene. Two different types of reactions, both that constitute 1,4-carboacetoxylations of the 1,3-diene, have been developed. In one of the reactions, Pd(II) catalyzes the oxidation of 1 to bicyclic compounds 2, and in the other, Pd(0) catalyzes the transformation of 1 to bicyclic compounds 3. The products 2 are useful for further synthetic tr0nsformations and undergo Diels-Alder reactions with dienophiles to give polycyclic ring systems.
- Loefstedt, Joakim,Franzen, Johan,Baeckvall, Jan-E.
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p. 8015 - 8025
(2007/10/03)
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- Synthesis of β-ionone
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Preparation of β-ionone by a reaction sequence starting from acetone is described.
- Vani,Chida,Srinivasan,Chandrasekharam,Singh
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p. 219 - 224
(2007/10/03)
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- Reactions of Unsaturated Azides, 6 Synthesis of 1,2,3-Triazoles from Propargyl Azides by Rearrangement of the Azido Group. - Indication of Short-Lived Allenyl Azides and Triazafulvenes
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Treatment of 3-bromo-3-methyl-1-butyne (1) or 1-iodo-3-methyl-1,2-butadiene (3) with solutions of sodium azide affords 3-azido-3-methyl-1-butyne (5) which reacts already at room temperature to 1,2,3-triazoles 8-11.Structures of 5 and 8-11 are verified by independent syntheses and spectroscopic data although in part other assignments of structures have been published.The preparation of 1H-1,2,3-triazoles via propargyl azides is carried out in the presence of various nucleophiles and investigated by means of 15N-labelled starting material as well as optically active 3-azido-1-butyne (R-21).The only mechanism compatible with all results includes short-lived allenyl azides and triazafulvenes.Thus, propargyl azide 14 rearranges to allenyl azide 16 leading to triazafulvene 18 by rapid ring closure.Finally, 18 is trapped by nucleophiles to give triazole 17.The conversion of various propargyl compounds into N-unsubstituted 1H-1,2,3-triazoles 23, 41, 44, 46, 50, and 51 is effected by a one-pot procedure without isolation of 14 and turns out to be a convenient method to prepare these heterocycles. - Key Words: Allenyl azides, ring closure of / Propargyl azides, rearrangement of / Triazafulvenes, nucleophilic addition to / Triazoles, preparation of
- Banert, Klaus
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p. 911 - 918
(2007/10/02)
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- SYNTHESIS OF TERTIARY ACETYLENIC ALCOHOLS AND THEIR ETHERS IN THE KOH-DMSO SYSTEM.
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The authors developed a universal single-stage method of synthesis of acetylenic alcohol ethers, including allyl and propargyl. Conducting the synthesis in one preparative stage is due to the fact that etherification of acetylenic alcohol alcoholates by organyl halides takes place in the same apparatus without separation of the intermediate product, i. e. , the synthesis is actually reduced to successive treatment of ketone with acetylene (or vinylacetylene) and organyl halides. The yield of ethers is weakly dependent on the structure of the ketone and organyl halide radicals. In the case of propargyl chloride, the formation of dipropargyl ether is observed (yield of 5%), which indicates the possibility of partial hydrolysis of the halide.
- Trofimov,Sobenina,Korostova,Mikhaleva,Shishov,Fel'dman,Shevchenko,Vasil'ev
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p. 1291 - 1295
(2007/10/02)
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- Cycloaddition Reactions of Allenyl Cations with Cyclopentadiene
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Propargyl halides R1-C=-C-CR2R3X (14) and cyclopentadiene react with zinc halide catalysis in ether/dichloromethane solution to give 3-halogenobicycloocta-2,6-dienes 13 (R1 = alkyl) or 5-(α-halogenobenzylidene)norbornenes 15 (R1 = aryl).The reactions are interpreted by stepwise - and -cycloadditions of intermediate allenyl cations 1, proceeding via propargylcyclopentenyl cations 5 and bicyclic vinyl cations 9 or 12.If the reactions are initiated by equimolar amounts of silver trifluoroacetate, quenching products of all postulated intermediates are isolated.The relative energies of the intermediate carbenium ions are estimated on the basis of force field calculations and of gas phase stabilities of simple carbocations.Stereochemical studies indicate that the addition reactions proceed via the compact transition state 42 rather than 41.The zinc chloride catalysed reaction of propargyl chloride 14e with cyclopentadiene yields the 2:1 product 17 (structurally assigned by X ray analysis) in addition to the 1:1 product 15e.The formation of 17 is rationalised by a -cycloaddition of allenyl cation 1 with cyclopentadiene.
- Mayr, Herbert,Halberstadt-Kausch, Inge K.
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p. 3479 - 3515
(2007/10/02)
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- Applications of Phase Transfer Catalysis, 24. - Note on the Acceleration of Reactions between Alkynes and Carbonyl Compounds
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Reactions between the title compounds in toluene/15percent aqueous sodium hydroxide are accelerated by the presence of N(C4H9)Br.
- Dehmlow, Eckehard V.,Shamout, Abdul Rahman
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p. 1750 - 1752
(2007/10/02)
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- The reaction of some propargyl alcohols with benzeneselenenyl chloride
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The reaction of benzeneselenenyl chloride with twenty-two propargyl alcohols in methylene chloride solution is reported.Products of both Markownikoff and anti-Markownikoff regiochemistry are formed in an anti stereospecific manner.The regioselectivity or specificity is found to be very dependent upon the nature of the substituents geminal to the alcoholic moiety.In general the presence of bulky substituents geminal to the alcoholic moiety tend to favour formation of the anti-Markownikoff adduct under conditions of kinetic control.The Markownikoff adducts are found to be favoured thermodynamically.
- Garratt, Dennis G.,Beaulieu, Pierre L.,Morisset, Veronique M.
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p. 927 - 934
(2007/10/02)
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- Hydroformylation of mono-α-olefins and mono-α-acetylenes
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This invention relates to improvements in certain catalytic reactions, namely, hydrogenation, hydroformylation and carbonylation reactions.
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- Akenyl(or alkynyl) 9-xanthenyl ether compounds
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The compounds are alkenyl(and alkynyl) 9-xanthenyl ethers, for example allyl 9-xanthenyl ether, which are inhibitors of gastric acid secretion.
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- Catalytic rearrangement
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Process for converting secondary and tertiary acetylenic carbinols to the corresponding alpha,beta-unsaturated carbonyl compounds by rearranging the carbinol with (trilower alkyl-, tricycloalkyl-, triaryl- or triarylalkyl-siloxy)-vanadium oxide catalyst in the presence of a silanol where either the vanadium oxide or the silanol contains a phenyl group substituted with at least one electron withdrawing group.
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