56038-53-0Relevant articles and documents
Iron-Catalyzed Vinylzincation of Terminal Alkynes
Huang, Qiang,Su, Yu-Xuan,Sun, Wei,Hu, Meng-Yang,Wang, Wei-Na,Zhu, Shou-Fei
supporting information, p. 515 - 526 (2022/01/08)
Organozinc reagents are among the most commonly used organometallic reagents in modern synthetic chemistry, and multifunctionalized organozinc reagents can be synthesized from structurally simple, readily available ones by means of alkyne carbozincation. However, this method suffers from poor tolerance for terminal alkynes, and transformation of the newly introduced organic groups is difficult, which limits its applications. Herein, we report a method for vinylzincation of terminal alkynes catalyzed by newly developed iron catalysts bearing 1,10-phenanthroline-imine ligands. This method provides efficient access to novel organozinc reagents with a diverse array of structures and functional groups from readily available vinylzinc reagents and terminal alkynes. The method features excellent functional group tolerance (tolerated functional groups include amino, amide, cyano, ester, hydroxyl, sulfonyl, acetal, phosphono, pyridyl), a good substrate scope (suitable terminal alkynes include aryl, alkenyl, and alkyl acetylenes bearing various functional groups), and high chemoselectivity, regioselectivity, and stereoselectivity. The method could significantly improve the synthetic efficiency of various important bioactive molecules, including vitamin A. Mechanistic studies indicate that the new iron-1,10-phenanthroline-imine catalysts developed in this study have an extremely crowded reaction pocket, which promotes efficient transfer of the vinyl group to the alkynes, disfavors substitution reactions between the zinc reagent and the terminal C–H bond of the alkynes, and prevents the further reactions of the products. Our findings show that iron catalysts can be superior to other metal catalysts in terms of activity, chemoselectivity, regioselectivity, and stereoselectivity when suitable ligands are used.
One-Pot Conversion of Aldehydes and Ketones into 1-Substituted and 1,4-Disubstituted 1,3-Enynes
Cabezas, Jorge A.,Poveda, Rebeca R.,Brenes, José A.
, p. 3307 - 3321 (2018/09/04)
Sequential treatment of 2,3-dichloropropene with magnesium and n -BuLi generates the operational equivalent of 1,3-dilithiopropyne, which upon treatment with aldehydes or ketones, produces the corresponding alkoxy lithium acetylide intermediates. Reaction of this alkoxide with tosyl chloride, and t -BuLi produces 1-substituted, or 1,1-disubstituted 1,3-enynes in a one-pot reaction. When this lithium acetylide intermediates, obtained by this procedure, were used to perform palladium-catalyzed cross-coupling reactions, followed by addition of thionyl chloride and pyridine, 1,4-disubstituted or 1,1,4-trisubstituted 1,3-enynes were obtained in a one-pot protocol.
A novel ketone olefination via organozinc reagents in the presence of diphenyl phosphite
Cui, Hua,Li, Ying,Zhang, Songlin
supporting information, p. 2862 - 2869 (2012/11/07)
Carbonyl compounds react with organozinc reagents in the presence of diphenyl phosphite to give the corresponding olefins. A variety of 1,3-dienes and unsaturated esters were obtained in moderate to excellent yields under mild conditions. The Royal Society of Chemistry 2012.
Gold catalysis: Evidence for the in-situ reduction of gold(III) during the cyclization of allenyl carbinols
Hashmi, A. Stephen K.,Blanco, M. Carmen,Fischer, Dirk,Bats, Jan W.
, p. 1387 - 1389 (2007/10/03)
Products of an oxidative coupling were obtained in the gold(III)-catalyzed cycloisomerization of tertiary allenyl carbinols. The absence of reduced organic products and an increase of these coupling products with the amount of gold(III) catalyst suggests
