- Photocatalytic Annulation-Alkynyl Migration Strategy for Multiple Functionalization of Dual Unactivated Alkenes
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A novel photoredox catalysis for multiple functionalization of two different types of unactivated alkenes in a single operation was reported through a conceptually new mode of annulation-alkynyl migration. A wide array of cyclopentane carboxylates were sy
- Zhao, Qi,Hao, Wen-Juan,Shi, Hao-Nan,Xu, Ting,Tu, Shu-Jiang,Jiang, Bo
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- Gold-Catalyzed Hydroamination of Propargylic Alcohols: Controlling Divergent Catalytic Reaction Pathways to Access 1,3-Amino Alcohols, 3-Hydroxyketones, or 3-Aminoketones
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A versatile approach to the valorization of propargylic alcohols is reported, enabling controlled access to three different products from the same starting materials. First, a general method for the hydroamination of propargylic alcohols with anilines is described using gold catalysis to give 3-hydroxyimines with complete regioselectivity. These 3-hydroxyimines can be reduced to give 1,3-amino alcohols with high syn selectivity. Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway. The utility of the new chemistry was exemplified by the one-pot synthesis of a selection of N-arylpyrrolidines and N-arylpiperidines. A mechanism for the hydroamination has been proposed on the basis of experimental studies and density functional theory calculations.
- Laserna, Victor,Porter, Michael J.,Sheppard, Tom D.
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p. 11391 - 11406
(2019/09/30)
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- Alkynylation of aldehydes mediated by zinc and allyl bromide: a practical synthesis of propargylic alcohols
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Abstract: A practical synthesis of propargylic alcohols was developed by alkynylation of aldehydes mediated by zinc and allyl bromide. Aromatic, aliphatic and vinyl aldehydes react with phenylacetylene or 1-hexyne to obtain various propargylic alcohols at room temperature in up to 98% yield. This method is characterized with inexpensive materials, wide substrate scope, and mild reaction conditions, and is also easy to scale up. In addition, this protocol is applicable to the alkynylation of α-ketone esters and epoxides to generate α-tertiary-hydroxy esters and α-alkynyl alcohols, respectively. Graphical Abstract: [Figure not available: see fulltext.].
- Zhou, Ji-Cai,Zhao, Lei,Li, Yuan,Fu, Ding-Qiang,Li, Zi-Cheng,Huang, Wen-Cai
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p. 4283 - 4294
(2017/06/20)
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- Palladium-catalyzed coupling of propargylic carbonates with N-tosylhydrazones: Highly selective synthesis of substituted propargylic N-sulfonylhydrazones and vinylallenes
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An efficient palladium-catalyzed coupling of propargylic carbonates (1) with N-tosylhydrazones (2, 2′) has been carried out. A wide range of propargylic N-sulfonylhydrazones (3) and multisubstituted vinylallenes (4) can be obtained selectively by using either [PdCl2(CH3CN) 2] or [Pd2(dba)3] as catalysts. (dba=trans,trans-dibenzylideneacetone, dppp=propane-l,3- diylbis(diphenylphosphane), Ts=4-toluenesulfonyl.) Copyright
- Chen, Zi-Sheng,Duan, Xin-Hua,Wu, Lu-Yong,Ali, Shaukat,Ji, Ke-Gong,Zhou, Ping-Xin,Liu, Xue-Yuan,Liang, Yong-Min
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p. 6918 - 6921
(2011/07/08)
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- P(PhCH2NCH2CH2)3N: An efficient Lewis base catalyst for the synthesis of propargylic alcohols and Morita-Baylis-Hillman adducts via aldehyde alkynylation
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(Chemical Equation Presented) Proazaphosphatrane P(PhCH2NCH 2CH2)3N (1a) is an efficient catalyst for the addition of aryl trimethylsilyl alkynes to a variety of aromatic, aliphatic, and heterocyclic aldehydes i
- Wadhwa, Kuldeep,Chintareddy, Venkat Reddy,Verkade, John G.
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supporting information; experimental part
p. 6681 - 6690
(2009/12/30)
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- An atom-economic and selective ruthenium-catalyzed redox isomerization of propargylic alcohols. An efficient strategy for the synthesis of leukotrienes
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Catalytic ruthenium complexes in conjunction with an indium cocatalyst and Broensted acid isomerize primary and secondary propargylic alcohols in good yields to provide trans enals and enones exclusively. Readily available indenylbis(triphenylphosphine)ruthenium chloride, in the presence of indium triflate and camphorsulfonic acid, gives the best turnover numbers and reactivity with the broadest range of substrates. Deuterium labeling experiments suggest that the process occurs through propargylic hydride migration followed by protic cleavage of the resultant vinylruthenium intermediate. Application of this method to the synthesis of leukotriene B4 demonstrates its utility and extraordinary selectivity.
- Trost, Barry M.,Livingston, Robert C.
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supporting information; experimental part
p. 11970 - 11978
(2009/02/05)
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