Reaction of CH2Br2 with CBr2F2 and alkenes 1a–e in the presence of 60% aqueous KOH and tetrabutylammonium hydrogensulphate as a catalyst affords gem-difluorocyclopropanes 2a–e.
Kamel,M. et al., Chemische Berichte, 1976, vol. 109, p. 2351 - 2369
作者:Kamel,M. et al.
DOI:——
日期:——
Synthese von α-Fluoracrylsäure und Derivaten
作者:K.-R. Gassen、D. Bielefeldt、A. Marhold、P. Andres
DOI:10.1016/s0022-1139(00)80116-5
日期:1991.12
Three new routes to derivatives of alpha-fluoracrylic acid, including a laboratory synthesis and a large-scale method, are reported. The processes are (i) addition of elementary fluorine to acrylic esters and subsequent elimination of HF; (ii) addition of difluorocarbene to isopropenyl methyl ether, oxidation via ring opening and dehalogenation; and (iii) 'nitrofluorination' of 2,3-dichloropropene, hydrolysis and dechlorination.
A photoprecursor for difluorocarbene
作者:Yigang He、David M. Lemal
DOI:10.1016/s0022-1139(02)00274-9
日期:2003.1
4,4-Difluoropyrazolidine-3,5-dione was synthesized as a precursor for the corresponding pyrazolinedione, envisioned as a photochemical source of difluorocarbene. However, this azo compound proved to be far too unstable. In contrast, 10,10-difluorobicyclo[4.3.1]deca-1,3,5-triene, readily synthesized from indane, was found to be a practical source of difluorocarbene for photochemical as well as thermal cyclopropanation reactions. (C) 2002 Elsevier Science B.V All rights reserved.
gem-Difluorocyclopropanes: an improved method for their preparation