4895-47-0Relevant academic research and scientific papers
Efficient Difluoromethylation of Alcohols Using TMSCF2Br as a Unique and Practical Difluorocarbene Reagent under Mild Conditions
Xie, Qiqiang,Ni, Chuanfa,Zhang, Rongyi,Li, Lingchun,Rong, Jian,Hu, Jinbo
supporting information, p. 3206 - 3210 (2017/03/17)
A general method for the efficient difluoromethylation of alcohols using commercially available TMSCF2Br (TMS=trimethylsilyl) as a unique and practical difluorocarbene source is developed. This method allows primary, secondary, and even tertiary alkyl difluoromethyl ethers to be synthesized under weakly basic or acidic conditions. The reaction mainly proceeds through the direct interaction between a neutral alcohol and difluorocarbene, which is different from the difluoromethylation of phenols. Moreover, alcohols containing other moieties that are also reactive toward difluorocarbene can be transformed divergently by using TMSCF2Br. This research not only solves the synthetic problem of difluorocarbene-mediated difluoromethylation of alcohols, it also provides new insights into the different reaction mechanisms of alcohol difluoromethylation and phenol difluoromethylation with difluorocarbene species.
Syntheses and characterization of bis(trifluoromethyl)phosphino naphthalenes and acenaphthenes
Wawrzyniak, Piotr,Slawin, Alexandra M. Z.,Woollins, J. Derek,Kilian, Petr
experimental part, p. 85 - 92 (2010/03/03)
Syntheses of heteroleptic 1,8-bis(phosphino)naphthalenes and 5,6-bis(phosphino)acenaphthenes were attempted using several synthetic strategies. Reaction of aryllithium with triphenylphosphite gave ArP(OPh) 2 (Ar = substituted naphthalene or acenaphthene), which was transformed into ArP(CF3)2, using a nucleophilic trifluoromethylation reaction with Me3SiCF3/CsF. The importance of the correct choice of solvent for the trifluoromethylation reactions is discussed. The incompatibility of ArP(CF3)2 with organolithium hampered the attachment of the second phosphine functionality to the organic backbone. Tetraphenoxyethylene was obtained in a small amount as a side product in the trifluoromethylation reaction. Selected new compounds were characterized by single-crystal X-ray diffraction. The Royal Society of Chemistry 2010.
Aryloxy Radicals from Diaryloxydiazirines: α-Cleavage of Diaryloxycarbenes or Excited Diazirines?
Fede, Jean-Marie,Jockusch, Steffen,Lin, Nan,Moss, Robert A.,Turro, Nicholas J.
, p. 5027 - 5030 (2007/10/03)
(Equation presented) The synthesis of diaryloxydiazirines, precursors to diaryloxycarbenes, is described. Thermolyses of the diazirines afford anticipated carbene products, but photolyses afford both carbenes and aryloxy radicals by α-scission. UV spectra of the carbenes and radicals are observed.
Diaryloxycarbenes from oxadiazolines
Lu,Reid,Warkentin
, p. 319 - 327 (2007/10/03)
Symmetric and unsymmetric 2,2-diaryloxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines were synthesized by oxidative cyclization of aryloxycarbonyl hydrazones of acetone with lead tetraacetate and subsequent treatment of the product mixture with a phenol in acidic solution. Thermolysis of the oxadiazolines in benzene solution at 110°C afforded carbonyl ylide intermediates that cyclize, in part, to the corresponding 2,2-diaryloxyoxirane intermediates. The oxiranes, which were not observed, are required to account for the 1,1-diaryloxy-2-methylpropenes (ketene acetals) that were isolated. Most of the carbonyl ylides fragment to acetone and diaryloxycarbenes. The latter form dimers (tetraaryloxyethenes) or they can be trapped with phenols to form orthoformates. Diphenoxycarbene was also trapped with dimethyl acetylenedicarboxylate (DMAD). The method appears to be the first for generating the parent diphenoxycarbene under relatively mild conditions in solution, and the only one to date for generating unsymmetrically substituted diaryloxycarbenes. Minor competing fragmentations of the oxadiazolines to 2-diazopropane and the appropriate diaryl carbonates, were also observed.
