- One-Pot γ-Lactonization of Homopropargyl Alcohols via Intramolecular Ketene Trapping
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A one-pot γ-lactonization of homopropargyl alcohols via an alkyne deprotonation/boronation/oxidation sequence has been developed. Oxidation of the generated alkynyl boronate affords the corresponding ketene intermediate, which is trapped by the adjacent hydroxy group to furnish the γ-lactone. We have optimized the conditions as well as examined the substrate scope and synthetic applications of this efficient one-pot lactonization.
- Yamane, Daichi,Tanaka, Haruna,Hirata, Akihiro,Tamura, Yumiko,Takahashi, Daichi,Takahashi, Yusuke,Nagamitsu, Tohru,Ohtawa, Masaki
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supporting information
p. 2831 - 2835
(2021/05/05)
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- Synthesis of Cyclopropanes via 1,3-migration of acyloxy groups triggered by formation of α-Imino Rhodium Carbenes
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A novel and highly efficient synthetic approach to cyclopropanes was realized via 1,3-migration of acyloxy groups triggered by α-imino rhodium carbenes. Excellent chemoselectivity ensured broad compatibility of common functional groups. Merits such as readily available substrates, mild reaction conditions, and time-saving processes qualified this transformation as an attractive alternative strategy to synthesize multifunctionalized cyclopropanes. Primary investigations and discussion on the mechanism are presented.
- Xu, Ze-Feng,Liu, Jincheng,Chang, Xin,Chen, Tao,Xu, Huaping,Duan, Shengguo,Li, Chuan-Ying
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supporting information
p. 5163 - 5169
(2020/07/16)
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- TBAI/K2S2O8 Initiated Radical Cyclization to Synthesize β- Arylsulfonyl Naphthalenes from Homopropargylic Alcohols and Sulfonyl Hydrazides
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A metal-free radical addition method for the synthesis of β-arylsulfonyl naphthalenes with homopropargylic alcohols and sulfonyl hydrazides has been developed. In this reaction, sulfonyl hydrazide is employed as the source of sulfonyl radical to produce the desired sulfone directly. There is the first example for homopropargylic alcohol through direct intramolecular addition of vinyl radical to arenes with sulfonyl radical, which is initiated by the TBAI/K2S2O8 reaction system and generates the desired products in moderate yields. (Figure presented.).
- Yang, Xiaodong,Zhao, Lianbiao,Yuan, Bingxiang,Qi, Zhenjie,Yan, Rulong
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supporting information
p. 3248 - 3253
(2017/09/06)
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- Electrophilic cyclization and intermolecular acetalation of 2-(4- hydroxybut-1-yn-1-yl)benzaldehydes: Synthesis of diiodinated diepoxydibenzo[c,k][1,9]dioxacyclohexadecines
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An expedient strategy for the preparation of diiodinated diepoxydibenzo[c,k][1,9]dioxacyclohexadecines from readily available 2-(4-hydroxybut-1-yn-1-yl)- benzaldehydes through electrophile-triggered tandem cyclization/ intermolecular acetalation sequence
- Wang, Jia,Zhu, Hai-Tao,Chen, Si,Luan, Cheng,Xia, Yu,Shen, Yi,Li, Ying-Xiu,Hua, Yingxi,Liang, Yong-Min
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p. 10641 - 10649
(2018/05/31)
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- Palladium-Catalyzed One-Pot Conversion of Aldehydes and Ketones into 4-Substituted Homopropargyl Alcohols and 5-En-3-yn-1-ols ?
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Sequential treatment of 2,3-dichloropropene with magnesium and n-BuLi generated the equivalent of 1,3-dilithiopropyne, which adds regiospecifically to aldehydes and ketones to produce homopropargyl alcohols. The lithium acetylide intermediate formed in this protocol can be further reacted with aromatic and vinyl halides, under palladium catalysis, to produce 4-substituted homopropargyl alcohols and 5-en-3-yn-1-ols, respectively, in one-pot with good overall yields.
- Umana, Christian A.,Cabezas, Jorge A.
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p. 9505 - 9514
(2017/09/23)
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- Re-engineering of PIP3-antagonist triazole PITENIN's chemical scaffold: Development of novel antifungal leads
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A novel 4-(1-phenyl-1-hydroxyethyl)-1-(o-hydroxyphenyl)-1H-1,2,3-triazole was designed by integrating the structural features of triazole PITENIN anticancer agents and the azole class of antifungal drugs. A two-step protocol comprising the Barbier proparg
- Pulya, Sravani,Kommagalla, Yadagiri,Sant, Duhita G.,Jorwekar, Shweta U.,Tupe, Santosh G.,Deshpande, Mukund V.,Ramana, Chepuri V.
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p. 11691 - 11701
(2016/02/09)
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- Boronic acid/Br?nsted acid co-catalyst systems for the synthesis of 2: H -chromenes from phenols and α,β-unsaturated carbonyls
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Protocols for the synthesis of substituted 2H-chromenes from α,β-unsaturated carbonyls and phenols are described. Optimal combinations of arylboronic acids and Br?nsted acids have been identified, such that both can be employed in catalytic quantities to accelerate these condensations. The method has been used to synthesize a variety of substituted 2H-chromenes, as well as photochromic naphthopyrans. The use of pentafluorophenylboronic acid and diphenylphosphinic acid enabled an expansion of the electrophile scope to include α,β-unsaturated ketones. Hall's 'phase-switching' of boronic acids has been exploited to achieve the separation of the two co-catalysts from unpurified reaction mixtures by a simple liquid-liquid extraction.
- Dimakos, Victoria,Singh, Tishaan,Taylor, Mark S.
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p. 6703 - 6711
(2016/07/21)
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- Copper-catalyzed one-pot trifluoromethylation/aryl migration/carbonyl formation with homopropargylic alcohols
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A novel copper-catalyzed one-pot functionalization of homopropargylic alcohols that involves trifluoromethylation, aryl migration, and formation of a carbonyl moiety has been developed. This reaction constitutes the first direct conversion of homopropargy
- Gao, Pin,Shen, Yong-Wen,Fang, Ran,Hao, Xin-Hua,Qiu, Zi-Hang,Yang, Fan,Yan, Xiao-Biao,Wang, Qiang,Gong, Xiang-Jun,Liu, Xue-Yuan,Liang, Yong-Min
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supporting information
p. 7629 - 7633
(2014/08/05)
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- One-pot, solvent-free regioselective addition reactions of propargyl bromide to carbonyl compounds mediated by Zn-Cu couple
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A Barbier-type propargylation of carbonyl compounds with propargyl bromide has been achieved with reactive zinc-copper couple under solvent-free conditions. The reaction of aldehydes with propargyl bromide produced the unique homopropargyl alcohols in excellent yields at room temperature without the formation of homoallenyl alcohols. The ketones reacted with propargyl bromide to give the corresponding homopropargyl alcohols in good to excellent yields at -14 to -16 °C. The advantages of this method are excellent yields, short reaction time, high regioselectivity, and avoidance of the use of organic solvents.
- Ma, Xiaofang,Wang, Jin-Xian,Li, Shunxi,Wang, Ke-Hu,Huang, Danfeng
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experimental part
p. 8683 - 8689
(2009/12/24)
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- The intricate assembling of gem-diphenylpropargylic units
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While optimized procedures for selective propargylic - versus allenic - attack (in particular by alkynylsilanes) have proven to be compatible with many substitution patterns at the propargylic center, the case of diarylpropargyl electrophiles has remained problematic. The intrinsic reactivity of 1,1-diphenylpropargylic alcohols [R-C≡C-C(Ph2)OH (R = TMS, H, Me)] in the presence of various acids (and in the absence of additional nucleophile) has thus been systematically investigated. Whereas the monophenyl analogues [R-C≡C-CH(Ph)OH] afford the expected bis(phenylpropargyl) ethers, the diphenyl versions undergo complex but quite selective processes to afford various structural types: depending on the acid used, a diallene, an allenyne, an indenylallene, an indanone or a condensed tetra- and pentacycles were obtained. When the reactions were conducted in the presence of an alkynylsilane capable of playing the role of a competing nucleophile, the expected propargylic substitution products - dialkynyldiphenylmethanes or their isomers - were never observed. The hitherto unknown simple hydrocarbons diethynyl- and dipropynyl-diphenylmethane could, however, be obtained in low yields through a four-step sequence involving allenylidene- and alkynylruthenium intermediates. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Maraval, Valerie,Duhayon, Carine,Coppel, Yannick,Chauvin, Remi
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experimental part
p. 5144 - 5156
(2009/08/07)
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- A new method for the preparation of 1,3-dilithiopropyne: An efficient synthesis of homopropargyl alcohols
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Controlled dilithiation of propargyl bromide with two equivalents of n-butyllithium, in the presence of TMEDA, produces the operational equivalent of the dianion 1,3-dilithiopropyne. The latter reacts efficiently with aldehydes and ketones to produce homo
- Cabezas, Jorge A,Pereira, Albán R,Amey, Adam
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p. 6819 - 6822
(2007/10/03)
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- Highly selective synthesis of acetylenic alcohols promoted by metallic dysprosium in the presence of mercuric chloride
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Promoted by metallic dysprosium, carbonyl compounds react smoothly with propargyl bromide to afford the corresponding homopropargylic alcohols in good to excellent yields without observation of allenic alcohols. In addition, this reaction is regioselective and chemoselective.
- Li, Zhiming,Jia, Yu,Zhou, Jingyao
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p. 2515 - 2524
(2007/10/03)
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- Regioselective propargylation of aldehydes and ketones by electrochemical reaction using zinc and aluminum anodes
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Electrochemical propargylation of aldehydes and ketones with unsubstituted or α-substituted propargylic bromides using platinum cathode and zinc anode proceeded efficiently under mild conditions to give the corresponding homopropargyl alcohols exclusively
- Kurono, Nobuhito,Sugita, Kazuya,Tokuda, Masao
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p. 847 - 854
(2007/10/03)
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- Propargylation of carbonyl compounds: An efficient method for the synthesis of homopropargyl alcohols
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Controlled dilithiation of allene, with two equivalents of n- butyllithium, produces the propargyl dianion 5. The latter couples efficiently with carbonyl compounds to produce homopropargyl alcohol in high yields.
- Cabezas, Jorge A.,Alvarez, Leonardo X.
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p. 3935 - 3938
(2007/10/03)
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- Organoboranes for Synthesis. 15. B-Allenyl-9-BBN: A Highly Regiospecific and Chemoselective Reagent for Allenylboration of Representative Carbonyl Compounds, Leading to Homopropargylic Alcohols and Amines
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Reactions of B-allenyl-9-BBN (11) with representative carbonyl compounds, such as aldehydes, ketones, acid chlorides, carboxylic acid esters, and imines, proceed cleanly with the allenyl moiety undergoing transfer to the carbonyl or imine carbon, with allenic to propargylic rearrangement, and the boron moiety to the carbonyl oxygen or imine nitrogen.A simple oxidation with alkaline hydrogen peroxide results in the formation of the corresponding homopropargylic alcohols and amines in excellent yields.Aldehydes, ketones, and imines react in a 1:1 stoichiometry, while acid chlorides and carboxylic acid esters react with 2 equiv of the reagent.The relative reactivities of representative aldehydes, ketones, and esters toward 11 were also explored.Besides being highly regiospecific, the reagent 11 also possesses a remarkable chemoselectivity.B-Allenyl-9-BBN can distinguish between less and more sterically hindered aldehydes, ketones, and esters, making possible the clean and selective propargylboration of a desired carbonyl group in complex organic molecules containing less reactive functional groups.
- Brown, Herbert C.,Khire, Uday R.,Narla, Gowriswari,Racherla, Uday S.
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p. 544 - 549
(2007/10/02)
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- RADIKALISCHE REAKTIONSWEGE BEI THERMISCH INDUZIERTEN UMSETZUNGEN VON ZIRCONOCENKOMPLEXEN
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The formation of products 2, 3 and 4(a-l) from both the reaction of εta2-bezophenone zirconocene 1 with alkyl halides and the thermolysis of the α-(Cp2ZrCl)-substituted benzhydrylmethylether 9, the latter proceeding with anchimeric assistance of the metal, can be understood assuming a stepwise reaction path through radical intermediates.The proposed intermediate transition-metal benzophenone ketyl 12 exhibits a reaction pattern differing from analogous main-group-metal ketyls.
- Erker, G.,Rosenfeldt, F.
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p. 1285 - 1292
(2007/10/02)
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- REVERSAL OF THE BENZOPHENONE REACTIVITY UPON η2 -COMPLEXATION TO BIS( η5 -CYCLOPENTADIENYL)ZIRCONIUM
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Reversal of the carbonyl activity of benzophenone, serving as electron donor in single-electron transfer processes and acting as a proton acceptor through the 'carbonyl'carbon atom, is observed upon η2 -complexation to zirconocene.
- Rosenfeldt, Frank,Erker, Gerhard
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p. 1637 - 1640
(2007/10/02)
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