Esters as Radical Acceptors: β‐NHC‐Borylalkenyl Radicals Induce Lactonization by C−C Bond Formation/Cleavage on Esters
作者:Masaki Shimoi、Katsuhiro Maeda、Steven J. Geib、Dennis P. Curran、Tsuyoshi Taniguchi
DOI:10.1002/anie.201902001
日期:2019.5.6
Substituted propargyl acetates are converted into 4‐boryl‐2(5H)‐furanones upon thermolysis in the presence of an N‐heterocyclic carbene borane (NHC‐borane) and di‐tert‐butyl peroxide. The acetyl methyl group is lost during the reaction as methane. Evidence suggests that the reaction proceeds by a sequence of radical events including: 1) addition of an NHC‐boryl radical to the triple bond; 2) cyclization
Asymmetric Wacker‐Type Oxyallenylation and Azaallenylation of Cyclic Alkenes
作者:Shenghan Teng、Zhiwei Jiao、Yonggui Robin Chi、Jianrong Steve Zhou
DOI:10.1002/anie.201911961
日期:2020.2.3
Palladium-catalyzed three-component carboetherification of cyclic alkenes proceeded to give trans adducts exclusively with excellent enantioselectivity through a Wacker-type pathway. The reaction is also applicable to other oxygen nucleophiles, such as water, phenols, and carboxylic acids, as well as some electron-poor aryl amines.
Enantioselective Three‐Component Coupling of Heteroarenes, Cycloalkenes and Propargylic Acetates
作者:Shenghan Teng、Yonggui Robin Chi、Jianrong Steve Zhou
DOI:10.1002/anie.202014781
日期:2021.2.23
heteroarenes including indoles, pyrroles, activated furans and thiophenes. 2,3‐Disubstituted tetrahydrofurans and pyrrolidines are produced in trans configuration and excellent enantiomeric ratios. The reaction proceeds via Wacker‐type attack of nucleophilic heteroarenes on alkenes activated by allenyl PdII species.
Enantioselective Synthesis of Dihydropyrazoles by Palladium/Xu‐Phos‐Catalyzed Alleneamination of β, γ‐Unsaturated Hydrazones with Propargylic Acetates
作者:Shuting Zhang、Shuaijie Wu、Qiang Wang、Shiji Xu、Ying Han、Chao-Guo Yan、Junliang Zhang、Lei Wang
DOI:10.1002/anie.202300309
日期:——
A new robust palladium-catalyzed enantioselective alleneamination reaction of β,γ-unsaturated hydrazones with propargylic acetates is described. The salient features of this reaction include general substrate scope, well functional group tolerance, good yields and high enantioselectivities.
Synthesis of Multisubstituted Allenes by Palladium-Catalyzed Carboetherification of β,γ-Unsaturated Ketoximes with Propargylic Acetates
作者:Shuaijie Wu、Shuting Zhang、Jing Sun、Ying Han、Yidong Wang、Chao-Guo Yan、Lei Wang
DOI:10.1021/acs.orglett.3c01561
日期:2023.6.30
A highly efficient Pd-catalyzed carboetherification reaction of β,γ-unsaturated ketoximes with propargylic acetates is demonstrated. This method provides a practical protocol for accessing the incorporation of an allene moiety into 3,5-disubstituted and 3,5,5-trisubstituted isoxazolines. The salient features of this transformation include a broad substrate scope, good functional group tolerance, an