Development of Enantioselective Palladium‐Catalyzed Alkene Carboalkoxylation Reactions for the Synthesis of Tetrahydrofurans
作者:Brett A. Hopkins、Zachary J. Garlets、John P. Wolfe
DOI:10.1002/anie.201506884
日期:2015.11.2
The Pd‐catalyzed coupling of γ‐hydroxyalkenes with aryl bromides affords enantiomerically enriched 2‐(arylmethyl)tetrahydrofuran derivatives in good yield and up to 96:4 e.r. This transformation was achieved through the development of a new TADDOL/2‐arylcyclohexanol‐derived chiral phosphite ligand. The transformations are effective with an array of different aryl bromides, and can be used for the preparation
Oxidative cyclization of tertiary pentenol derivatives forming 2,5,5-trisubstituted THF rings and the total synthesis of cyclocapitelline
作者:Geoffrey A. Phillips、Cory Palmer、Andrew C. Stevens、Mathew L. Piotrowski、Daryl S.R. Dekruyf、Brian L. Pagenkopf
DOI:10.1016/j.tetlet.2015.09.064
日期:2015.10
The synthesis of 2,5,5-trisubstituted tetrahydrofuran rings was accomplished via the Mukaiyama aerobic oxidativecyclization of tertiary 5-pentenols employing the Co(nmp)2 catalyst. A variety of THFs were formed in moderate to good yield and diastereoselectivity. The method developed herein was successfully applied to an enantioselective total synthesis of cyclocapitelline.
Enone construction: A silver‐mediated olefin acylation reaction is described, in which five‐, six‐, and ‐seven‐membered rings, tetrasubstituted olefins, bridged bicycles, spirocycles, and benzoxepinones are prepared. Highly selective intermolecular reactions are coupled to a Nazarov cyclization for the effective preparation of cyclopentenones, including the core of modhephene (see scheme).
Catalytic Hydroxycyclopropanol Ring-Opening Carbonylative Lactonization to Fused Bicyclic Lactones
作者:Xinpei Cai、Weida Liang、Mingxin Liu、Xiating Li、Mingji Dai
DOI:10.1021/jacs.0c06179
日期:2020.8.12
A novel palladium-catalyzed ring opening carbonylative lactonization of readily available hydroxycyclopropanols was developed to efficiently synthesize tetrahydrofuran (THF) or tetrahydropyran (THP)-fused bicyclic γ-lactones, two privileged scaffolds often found in natural products. The reaction features mild reaction conditions, good functional group tolerability, and scalability. Its application
The key role of water in the heterogeneous permanganate oxidation of ω-hydroxy alkenes
作者:Sundarababu Baskaran、Imadul Islam、Padma S. Vankar、Srinivasan Chandrasekaran
DOI:10.1039/c39900001670
日期:——
Potassium permanganate–copper sulphate in dichloromethane in the presence of a catalytic amount of water effects a smooth oxidative cyclization of ω-hydroxyalkenes to ω-lactones in good yields with the net loss of one or more carbon atoms in the process.