38319-12-9Relevant academic research and scientific papers
A direct synthesis of trisubstituted allenes from propargyl alcohols via oxaphosphetane intermediates
Iwai, Kento,Yokoyama, Soichi,Asahara, Haruyasu,Nishiwaki, Nagatoshi
, p. 337 - 342 (2018/03/21)
A direct synthetic method for trisubstituted allenes from propargyl alcohol is provided; the synthesis proceeds via an oxaphosphetane intermediate. Functional groups such as for-myl and pyridyl exhibited a degree of tolerance during reaction without any protection. The alcohol dimethylated at the propargyl position afforded two structural isomers, allene and 1,3-diene. The product ratio was considerably influenced by the solvent. Allene was predominantly obtained when the reaction was conducted in cyclohexane, and the ratio was inverted by changing the solvent to dichloromethane. The prepared (2-pyridyl)allene served as a substrate for the copper(I) catalyzed cyclization reaction to afford 3,3-dimethylindolizine-2-one.
Synthesis of mono- and 1,3-disubstituted allenes from propargylic amines via palladium-catalysed hydride-transfer reaction
Nakamura, Hiroyuki,Ishikura, Makoto,Sugiishi, Tsuyuka,Kamakura, Takaya,Biellmann, Jean-Francois
experimental part, p. 1471 - 1477 (2008/10/09)
Mono- and 1,3-disubstituted allenes were synthesized from the corresponding propargylamines via palladium-catalysed hydride-transfer reaction. In the current transformation, propargylic amines can be handled as allenyl anion equivalents and introduced int
Synthesis of Allenes via Palladium-Catalyzed Hydrogen-Transfer Reactions: Propargylic Amines as an Allenyl Anion Equivalent
Nakamura, Hiroyuki,Kamakura, Takaya,Ishikura, Makoto,Biellmann, Jean-Francois
, p. 5958 - 5959 (2007/10/03)
Synthesis of allenes has been achieved by using palladium-catalyzed hydrogen-transfer reactions. Various propargylic amines, which were readily prepapred from iodobenzenes and propargylic amines by Sonogashira coupling reaction, underwent the hydrogen-tra
Highly chemoselective coupling of allenylstannanes with organic iodides promoted by Pd(PPh3)4/LiCl: An efficient method for the synthesis of substituted allenes
Huang, Chih-Wei,Shanmugasundaram, Muthian,Chang, Hao-Ming,Cheng, Chien-Hong
, p. 3635 - 3641 (2007/10/03)
An efficient method for the preparation of various monosubstituted arylallenes, disubstituted allenes and alkenylallenes via palladium-catalyzed coupling of allenylstannanes with aryl iodides or alkenyl iodides is described. The coupling reaction was carr
Photochemical and Thermal Hydrations of Aromatic Allenes. Evidence for Allyl and Vinyl Cation Intermediates
Rafizadeh, Karim,Yates, Keith
, p. 1500 - 1506 (2007/10/02)
The photohydration of aromatic allenes has been studied in water and in dilute aqueous sulfuric acid (0-25percent H2SO4).It was found that phenylallene (2a) and α-methylphenylallene (2b) undergo photohydration to give the corresponding cinnamyl alcohol derivatives.The proposed mechanism involves protonation of the central carbon of phenylallenes in their singlet excited state (S1).In contrast, (p-nitrophenyl)allene (2g) and (m-nitrophenyl)allene (2h) gave the corresponding (nitrophenyl)acetones.The mechanism for the formation of these ketones is believed to be due to initial protonation of the α- or γ-carbon atom of the (nitrophenyl)allene in the triplet excited state (T1).Phenylallenes with CN, CF3, and F substituents failed to photohydrate.The results of these photohydrations were compared with those of the much slower thermal hydrations in 70-83percent H2SO4.Phenylallenes 2a and 2b cyclized to the corresponding indene derivatives in 70percent H2SO4.Phenylallenes with NO2-substituents (2g-2h) underwent hydration to give the corresponding (nitrophenyl)acetones (expected products) and (nitrophenyl)-1-propanones (unexpected products) in 83percent H2SO4.Similar results were obtained with (m-cyanophenyl)allene.The formation of both types of ketone is discussed in terms of the intermediacy of a common vinyl cation intermediate.
