Patent ID: 6198008
Filing Date: 2001-03-06
Classification: C07C

Abstract:
In a process for preparing a fluoroolefin compound having the formula ##STR9##whereinAr is phenyl optionally substituted with any combination of from one to three halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, or 1- or 2-naphthyl optionally substituted with any combination of from one to three halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups;R is hydrogen and R.sub.1 is cyclopropyl, or R and R.sub.1 are each independently C.sub.1 -C.sub.4 alkyl, or R and R.sub.1 are taken together with the carbon atom to which they are attached to form a cyclopropyl group; and the configuration of the hydrogen atom and the fluorine atom about the double bond being mutually trans, which process comprisesoxidizing 5-bromo-2-fluorobenzeneboronic acid to form 5-bromo-2-fluorophenol,first reacting 5-bromo-2-fluorophenol with bromobenzene and a base to form 5-bromo-2-fluorophenyl phenyl ether,second reacting 5-bromo-2-fluorophenyl phenyl ether with magnesium to form the corresponding magnesium bromide, andthird reacting the magnesium bromide with a compound having the structural formula ##STR10##whereinAr, R and R.sub.1 are as described above, and Q is OC(O)CH.sub.3 or Br, in the presence of a transition metal catalyst selected from the group consisting of a cuprous halide, cuprous cyanide and Li.sub.2 CuCl.sub.4, wherein, prior to the oxidizingz step, the improvement compriseslithiating 1-bromo-4-fluorobenzene with at least about one molar equivalent of a lithium base in the presence of a solvent to form (5-bromo-2-fluorophenyl) lithium,reacting (5-bromo-2-fluorophenyl)lithium with a tri (C.sub.1 -C.sub.6 alkyl) borate to form a di(C.sub.1 -C.sub.6 alkyl) 5-bromo-2-fluorobenzeneboronate, andhydrolyzing the di(C.sub.1 -C.sub.6 alkyl) 5-bromo-2-fluorobenzeneboronate to form 5-bromo-2-fluorobenzeneboronic acid.