Lewis Base-Promoted Ring-Opening 1,3-Dioxygenation of Unactivated Cyclopropanes Using a Hypervalent Iodine Reagent
作者:Matthew H. Gieuw、Zhihai Ke、Ying-Yeung Yeung
DOI:10.1002/anie.201713422
日期:2018.3.26
A facile and effective system has been developed for the regio‐ and chemoselective ring‐opening/electrophilic functionalization of cyclopropanes through C−C bond activation by [bis(trifluoroacetoxy)iodo]benzene with the aid of the Lewis basic promoter p‐toluenesulfonamide. The p‐toluenesulfonamide‐promoted system works well for a wide range of cyclopropanes, resulting in the formation of 1,3‐diol products
Synergistic effect of additives on cyclopropanation of olefins
作者:Donghao Cheng、Deshun Huang、Yian Shi
DOI:10.1039/c3ob40751a
日期:——
An efficient cyclopropanation of olefins with Zn(CH2I)2, a catalytic amount of CCl3CO2H, and 1,2-dimethoxyethane at room temperature is described. A wide variety of olefins, including acid-sensitive substrates, can be cyclopropanated in 71–99% yield.
Intermolecular Electrophilic Bromoesterification and Bromoetherification of Unactivated Cyclopropanes
作者:Vincent Ming‐Yau Leung、Matthew H. Gieuw、Zhihai Ke、Ying‐Yeung Yeung
DOI:10.1002/adsc.201901665
日期:2020.5.12
1,3‐difunctionalization of cyclopropane is an useful organic transformation. The corresponding 1,3‐difunctionalized products are synthetic synthons and building blocks in many organic syntheses. Many existing ring‐opening difunctionalization methodologies rely primarily on the use of donor−acceptor cyclopropanes, while the difunctionalization of unactivated cyclopropanes is less exploited. In this
Stereoselective One-pot Dialkylation of<i>gem</i>-Dihalocyclopropanes by Means of Dialkylcopperlithiums
作者:Katuzi Kitatani、Tamejiro Hiyama、Hitosi Nozaki
DOI:10.1246/bcsj.50.1600
日期:1977.6
(2 and 3) is established by successive treatment with dibutylcopperlithium and several electrophiles. This sequence is found to be stereochemically controllable and is successfully applied to dl-sireninsynthesis. In contrast to the reaction of dibutylcopperlithium, dimethyl- and divinylcopperlithiums convert 1,1-dibromo-2-phenylcyclopropane (1a) into 1-bromo-1-methyl- and 1-bromo-1-vinyl-2-phenylcyclopropanes