Regiospecific synthesis of symmetrical (1E,3E) 2,3-difluoro-1,4-diphenyl-buta-1,3-dienes via palladium-catalyzed cross-coupling of (Z) 2-bromo-2-fluoroethenylbenzenes in presence of bis(pinacolato)diboron
摘要:
The cross-coupling reaction of (Z) 1-bromo-1-fluoroalkenes catalyzed by PdCl2(PPh3)(2)-2PPh(3) (3%) and CsF in Tetrahydrofuran (THF) in presence of bis(pinacolato)diboron led to (1E,3E) 2,3-difluoro-1,4-disubstituted-buta-1,3-dienes in high yields. (C) 2003 Elsevier B.V. All rights reserved.
The synthesis of α-fluoroacrylates and α-bromo-α-fluoroalkenes was achieved in very good yields using aldehydes and ketones, triphenylphosphine, diethylzinc as promoter, and ethyl dibromofluoroacetate or dibromofluoromethane, respectively. A change in the addition sequence was critical in order to obtain exclusively α-fluoroacrylates in good yields.
The reactions of fluorinated ylide, generated from tris(dimethylamino)phosphine and tribromofluoromethane, with simple aldehydes and reactive ketones gave the expected Wittig reaction products. How...
A halon-free method for the synthesis of ‑bromofluoroolefins utilizing ethyldibromofluoro-acetate is disclosed via a Wittigtypereaction. The reaction system takes advantage of inexpensive and readily available reagents. The method was applied to a wide variety of aryl aldehydes. Both electron donating and electron withdrawing moieties on the aryl ring were tolerated and the desired olefin products
Synthesis of 1-bromo-1-fluoroolefins was achieved in good yields via a Wittig reaction promoted by diethylzinc, even with nonactivated aldehydes and ketones as starting materials.
Stereoselective synthesis of 1-bromo-1-fluorostyrenes
作者:Aleksey V. Shastin、Vasiliy M. Muzalevsky、Elizabeth S. Balenkova、Valentine G. Nenajdenko
DOI:10.1070/mc2006v016n03abeh002282
日期:2006.1
The effective and stereoselective one-pot synthesis of 1-bromo-1-fluorostyrenes from aromatic aldehydes based on a catalytic olefination reaction was elaborated.