40358-71-2Relevant academic research and scientific papers
Hydrophobic encapsulated phosphonium salts - Synthesis of weakly coordinating cations and their application in wittig reactions
Moritz, Ralf,Wagner, Manfred,Schollmeyer, Dieter,Baumgarten, Martin,Müllen, Klaus
supporting information, p. 9119 - 9125 (2015/06/16)
Large and rigid tetraarylphosphonium tetrafluoroborate salts have been synthesized representing weakly coordinating cations with diameters of several nanometers. Divergent dendritic growth by means of thermal Diels-Alder cycloaddition was employed for the construction of the hydrophobic polyphenylene framework up to the third generation. X-ray crystal structure analysis of first-generation phosphonium tetrafluoroborate supported the rigidity of the non-collapsible shell around the phosphorus center and gave insight into solid-state packing and cation-anion distances. Copper(I)-catalyzed azide-alkyne ligation served as reliable method for the preparation of a first-generation triazolylphenyl hybrid phosphonium cation under mild reaction conditions. Furthermore, from the synthesis of triarylbenzylphosphonium bromides, Wittig precursors with unprecedented bulky substituents in the α-position were accessible. Employment of these precursors under Wittig conditions by treatment with base and subsequent reaction with aldehydes preferentially provided (Z)-olefins with bulky polyphenylene substituents. Just add salt: The application of benzylphosphonium bromides as Wittig precursors resulted in the formation of encapsulated phosphorus ylides, which were further reacted with aldehydes to yield novel olefins with bulky substituents. The stereochemical analysis of the obtained alkenes showed the exclusive formation of (Z)-isomers when aromatic aldehydes were employed and the sterically congested polyphenylene (Z)-stilbene derivative (see scheme) is reported.
Photoinduced electron-transfer bicyclopropenyl-benzene rearrangements of 2,2′,3,3′-tetraphenylbicyclopropenyls: A new mechanism via Dewar benzene
Ikeda, Hiroshi,Hoshi, Yosuke,Kikuchi, Yuka,Tanaka, Futoshi,Miyashi, Tsutomu
, p. 1029 - 1032 (2007/10/03)
(Equation presented) The 9,10-dicyanoanthracene-sensitized photoreaction of 1-methyl- and 1.1′-dimethyl-2,2′,3,3′- tetraphenylbicyclopropenyl gives the corresponding benzene and Dewar benzene derivatives, indicating that their photoinduced electron-transfer bicyclopropenyl-benzene rearrangements proceed via Dewar benzenes.
