19753-98-1Relevant academic research and scientific papers
Allenes through Horner-Wadsworth-Emmons olefination of alkenylphosphonates
Nagaoka, Yasuo,Inoue, Hideki,Tomioka, Kiyoshi
, p. 1843 - 1846 (2002)
Mono- and di-substituted allenes 5 were synthesized by successive Horner-Wadsworth-Emmons olefination starting from methylene-bisphosphonate 1 and two carbonyl compounds. The key to success is KH or KH-18-crown-6 as a base for the second HWE olefination o
Enantioselective A3 Reactions of Secondary Amines with a Cu(I)/Acid-Thiourea Catalyst Combination
Zhao, Chenfei,Seidel, Daniel
, p. 4650 - 4653 (2015)
Pyrrolidine and related amines undergo asymmetric A3 reactions in the presence of copper iodide and an easily accessible cocatalyst possessing both a carboxylic acid and a thiourea moiety. Propargylamines are obtained with up to 96% ee, and catalyst loadings can be as low as 1 mol %. Pyrrolidine-derived propargylamines, in the absence of directing groups, can be transformed to the corresponding allenes without loss of enantiopurity.
The Polarized Absoption Spectrum of 1,3-Diphenyl-1,2-propadiene: Interaction between Mutually Perpendicular Equivalent ?-Electronic Systems
Okubo, Jun,Shimazaki, Takayasu,Sato, Shin-ichi,Shinozaki, Hiraku
, p. 1405 - 1411 (1994)
The polarized UV absorption spectrum of 1,3-diphenyl-1,2-propadiene (DPA) wasx measured in a stretched polymer film at 101 K, and the polarization directions of the lectronic absorption bands were determined.Pariser-Parr-Pople (PPP) calculations extended
Palladium-catalyzed coupling of stannyl allenes with aryl iodides
Aidhen,Braslau
, p. 789 - 797 (1994)
Substituted allenes are prepared by coupling stannyl allenes with aryl iodides under palladium(0) catalysis. A concise and versatile sequence starting from propargyl alcohols provides a route for the preparation of substituted allenes under extremely mild conditions.
Stereochemistry of the Palladium(0)-Catalyzed Phenylation of 1-Halogenoallenes
Elsevier, Cornelis J.,Vermeer, Peter
, p. 3042 - 3045 (1985)
The stereochemistry of the Pd4-catalyzed phenylation of the 1-halogenoallenes RCH=C=CHX (R=Ph, t-Bu; X=Cl, Br, or I) with phenylzinc reagents has been elucidated by using optically active 1-halogenoallenes.The products RCH=C=CHPh were obtained with a moderate to high degree of inversion of configuration around the allenyl moiety when X was Cl and Br.When X was I, retention of configuration was observed.A rationalization of the results is given on the basis of two competing processes, viz., insertion of palladium in the C-X bond (oxidative addition) to give RCH=C=CH(Pd2X) with retention of configuration and a Pd2-induced anti-SN2'-like reaction followed by a suprafacial -shift of the Pd2 group leading to RCH=C=CH(Pd2X) with inversion of the configuration.For the latter reaction mode, such an allenyl palladium(0) intermediate was isolated and its absolute configuration determined.
Room Temperature Allenation of Terminal Alkynes with Aldehydes
Cui, Yifan,Li, Can,Ma, Shengming,Xiao, Junzhe,Xu, Haibo,Zhai, Yizhan,Zhang, Xue
supporting information, p. 25708 - 25713 (2021/11/09)
A gold-catalyzed room temperature allenation of terminal alkynes (ATA) with aldehydes affording 1,3-disubstituted allenes with diverse functional groups has been developed by identifying a gold(I) catalyst and an amine. The practicality of this reaction has been demonstrated by a ten gram-scale synthesis and the synthetic potentials have been demonstrated via various transformations and formal total synthesis of (?)-centrolobine. Mechanistic studies revealed that the gold catalyst, the aldehyde effect, the fluoroalkyl hydroxyl solvent (TFE or HFIP) and the structure of amine are vital in this room temperature ATA reaction.
Copper-Catalyzed 1,1-Boroalkylation of Terminal Alkynes: Access to Alkenylboronates via a Three-Component Reaction
Li, Ziyong,Sun, Jiangtao
supporting information, p. 3706 - 3711 (2021/05/31)
A copper-catalyzed three-component reaction of terminal alkynes, diazo compounds, and B2pin2 to prepare trisubstituted alkenylboronates has been developed. This difunctionalization of alkynes selectively occurs at the terminal carbon atom and proceeds via
Trifluoromethylation of Allenes: An Expedient Access to α-Trifluoromethylated Enones at Room Temperature
Brochetta, Massimo,Borsari, Tania,Gandini, Andrea,Porey, Sandip,Deb, Arghya,Casali, Emanuele,Chakraborty, Arka,Zanoni, Giuseppe,Maiti, Debabrata
, p. 750 - 753 (2019/01/04)
A silver(I) catalyzed regioselective trifluoromethylation of allenes using Langlois's salt (NaOSOCF3) is demonstrated. This transformation enables direct expedient access to α-trifluoromethylated acroleins, which are valuable synthons for a number of pharmaceuticals and agrochemicals containing vinyl-CF3 moieties. Versatility of this trifluoromethylation method has been established with good yield and excellent regioselectivity. Preliminary experiments and computational studies were carried out to elucidate the mechanistic insight of this protocol.
A convenient access to allylic triflones with allenes and triflyl chloride in the presence of (EtO)2P(O)H
Ni, Jixiang,Jiang, Yong,An, Zhenyu,Lan, Jingfeng,Yan, Rulong
supporting information, p. 7343 - 7345 (2019/06/27)
A simple method for the preparation of allylic triflones from allenes and triflyl chloride in the presence of (EtO)2P(O)H has been developed. The features of this reaction are catalyst-free and simple starting substrates. This method tolerates diverse functional groups and substituted allylic triflones are obtained in moderate to good yields.
Matched Coupling of Propargylic Carbonates with Cyclopropanols
Wu, Penglin,Jia, Minqiang,Lin, Weilong,Ma, Shengming
supporting information, p. 554 - 557 (2018/02/10)
The ring opening-coupling reaction of cyclopropanols with propargylic carbonates affording synthetically attractive allenyl ketones has been developed. The mechanism involves the ligand-exchange reaction of in situ formed allenyl palladium methoxide with cyclopropanols followed by carbon-carbon bond cleavage and reductive elimination. The reactions proceeded smoothly under mild reaction conditions with Pd(0)/XPhos catalysis in the absence of any external base and displayed a wide scope and application to a steroidal skeleton. The efficiency of chirality transfer and synthetic utility of the allene products have also been demonstrated.
