Enabling the Use of Alkyl Thianthrenium Salts in Cross‐Coupling Reactions by Copper Catalysis
作者:Cheng Chen、Minyan Wang、Hongjian Lu、Binlin Zhao、Zhuangzhi Shi
DOI:10.1002/anie.202109723
日期:2021.9.27
used groups in organic synthesis. Here, a a series of thianthreniumsalts have been synthesized that act as reliable alkylation reagents and readily engage in copper-catalyzed Sonogashira reactions to build C(sp3)−C(sp) bonds under mild photochemical conditions. Diverse alkyl thianthreniumsalts, including methyl and disubstituted thianthreniumsalts, are employed with great functional breadth, since
Reactions of magnesium alkoxides with trifluoromethanesulfonicanhydride or triflates gave corresponding symmetrical or unsymmetrical ethers in moderate to good yields under mild reaction conditions. The scope and limitations of the reaction are discussed.Key words: ethers, trifluoromethanesulfonicanhydride, triflates, magnesium alkoxides.
A series of new fluorocarbon and hydrocarbonN-heterocyclic (C-5-C-7) difluorooxymethylene-bridged liquidcrystals have been prepared. The impact of ring (C-5-C-7) as end group was investigated. Compounds with terminal N-heterocyclic 5- or 6-membered rings such as 3,4-difluoropyrrole, pyrrolidine, or pyridine, exhibited nematic phases (N). Whereas the terminal 3,3,4,4-tetrafluoropyrrolidine and 3,3
A new class of benzodioxocycloalkane‐based (C8–C10) liquidcrystals were prepared. The impact of ring (C8–C10) as end group was investigated. The 8–9 membered ring derivatives, 3a–3b, exhibited the nematic phases (N). The mesomorphicbehaviors were weakened with increasing the size of the ring. For the ?uorinated medium ring (C8–C10) 3d–3f, it was found only the fluorinated ten membered ring 3f showed
Bridgehead diphosphines in the bicyclo[3.3.3]undecane and bicyclo[4.4.4]tetradecane series: synthesis, structure and properties
作者:Roger W. Alder、Dianne D. Ellis、Rolf Gleiter、Christopher J. Harris、Holger Lange、A. Guy Orpen、David Read、Peter N. Taylor
DOI:10.1039/a800595h
日期:——
4-bis(1-phospholan-1-yl)butane. These included reaction of hydride adduct 15b with BunLi, and debenzylations of 1-benzyl-1-phosphonia-6-phosphabicyclo[4.4.4]tetradecane trifluoromethanesulfonate 16b and 1,6-dibenzyl-1,6-diphosphoniabicyclo[4.4.4]tetradecane bromide triflate 21 with LiAlH4. Reaction of cis-1,5-dibenzyl-1,5-diphosphacyclooctane with CH2(CH2OTf)2 gives 1,5-dibenzyl-1,5-diphosphoniabicyclo[3.3
通过1,k + 2-二磷酸双环[ k]的反应制备几种丙二酮二phosph盐8 。l .0]链烷烃6与α,ω-链烷二醇双三氟甲磺酸酯[双(三氟甲磺酸盐)];它们的性质在很大程度上取决于环的大小。1,6-二膦三环[4.4.4.0]十四烷双-三氟甲磺酸酯8d在酸性水溶液中稳定,并与亲核试剂[X = F –,MeO –,H –(来自BH 4 –)和R –(来自Grignard和烷基锂试剂)],得到13–18的部分X–P–P +键合时,氢氧根离子可生成一氧化二膦12b,但即使这样仍可保留某些P-P键合。但是,1,5-二膦三环[3.3.3.0]十一烷双-三氟甲磺酸酯8a不可逆地水解,并且比其[4.4.4.0]水解快得多。1,6-二膦三环[4.4.3.0]十三烷双-三氟甲磺酸酯8c与NaBH 4反应,得到氢化物加合物15a,该氢化物被Bu n Li去质子化,得到1,6-二磷双环[4.4.3]十三烷9c。然而,制备1,6-二磷酸双环[4