Direct allenol-based stereocontrolled access to substituted (E)-1,3-enynes
作者:Benito Alcaide、Pedro Almendros、Teresa Martínez del Campo
DOI:10.1039/c2ob26085a
日期:——
A stereoselective synthesis of 1-substituted (E)-2-aryl-but-1-en-3-ynes, including tetrasubstituted alkenes, has been developed from aryl-substituted α-allenols by treatment with the AcCl–NaOH (aqueous) system. This transformation might be explained through the elimination of acetic acid, made up of a δ-hydrogen and the acetate group in the initially formed α-allenic acetate.
Carbonyl Allenylations andPropargylations by 3-Chloro-1-propyne or 2-Propynyl Mesylateswith Tin(IV) Chloride and Tetrabutylammonium Iodide
作者:Yoshiro Masuyama、Akiko Watabe、Yasuhiko Kurusu
DOI:10.1055/s-2003-41012
日期:——
By the use of tin(IV) chloride and tetrabutylammonium iodidein dichloromethane, 3-chloro-1-propyne or 2-propynyl mesylate canbe applied to allenylation and propargylation of aldehydes (carbonylallenylation and propargylation) to produce a mixture of 1-substituted2,3-butadien-1-ols and 1-substituted 3-butyn-1-ols. 1-Substituted2-propynyl mesylates selectively cause carbonyl propargylation,while 3-substituted 2-propynyl mesylates cause carbonyl allenylation.
Chemoselectivity Switching in the Rhodium-Catalyzed Reactions of 4-Substituted-1-sulfonyl-1,2,3-triazoles with Allenols: Noticeable Differences between 4-Acyl- and 4-Aryl-Triazoles
作者:Benito Alcaide、Pedro Almendros、Israel Fernández、Teresa Martínez del Campo、Guillermo Palop、Mireia Toledano-Pinedo、Patricia Delgado-Martínez
DOI:10.1002/adsc.201801424
日期:2019.3.5
Tunable chemoselectivity (O‐ versus C‐attack) in the rhodium‐catalyzed reactions of allenols with 4‐substituted‐1‐sulfonyl‐1,2,3‐triazoles has been achieved through the replacement of the 4‐aryl substituent by a 4‐acetyl moiety.
Photoredox Propargylation of Aldehydes Catalytic in Titanium
作者:Francesco Calogero、Andrea Gualandi、Marco Di Matteo、Simone Potenti、Andrea Fermi、Giacomo Bergamini、Pier Giorgio Cozzi
DOI:10.1021/acs.joc.1c00521
日期:2021.5.7
A practical and effective photoredox propargylation of aldehydes promoted by 10 mol % of [Cp2TiCl2] is presented. No stoichiometric metals or scavengers are used for the process. A catalytic amount of the cheap and simply prepared organic dye 3DPAFIPN is used as the reductant for titanium. The reaction displayed a broad scope, and no traces of allenyl isomers were detected for simple propargyl bromide
Allenols versus Allenones: Rhodium-Catalyzed Regiodivergent and Tunable Allene Reactivity with Triazoles
作者:Benito Alcaide、Pedro Almendros、Sara Cembellín、Teresa Martínez del Campo、Guillermo Palop
DOI:10.1002/chem.201702468
日期:2017.10.4
2‐Pyrrolines and 6‐oxo‐hexa‐2,4‐dienals have been prepared through the divergent reactions of 1‐benzenesulfonyl‐4‐aryl‐1,2,3‐triazoles with functionalized allenes. The rhodium‐catalyzed reactions between allenols and 1‐benzenesulfonyl‐4‐aryl‐1,2,3‐triazoles yielded 2‐pyrrolines. This transformation is compatible with the presence of aliphatic, aromatic, heterocyclic, amide, and halogen functional groups