Facile synthesis of (E)-β-(trifluoromethyl)styrenes from halothane (HCFC-123B1)
摘要:
A practical and convenient synthesis of (E)-beta-(trifluoromethyl)styrenes has been achieved by the reaction of commercially available halothane (HCFC-123B1) and hydrazones prepared in advance in situ, in the presence of 1,2-ethylenediamine and a catalytic amount of CuCl2.2H(2)O at room temperature. The products showed acceptable to high yields and high to excellent stereoselectivity. This handy synthetic method provided easy access to a variety of (E)-beta-(trifluoromethyl)styrenes. (C) 2014 Elsevier B.V. All rights reserved.
A sustainable FeCl3-mediated method has been developed for the decarboxylativetrifluoromethylation of α,β-unsaturatedcarboxylicacids by using NaSO2CF3 as an economic and stable CF3 source. The reaction proceeds under mild condition and tolerates various functional groups. Advantageously, this method does not require an inert atmosphere and proceeds well in air at ambient temperature.
Oxy-trifluoromethylation of di-substituted styrenes and dienes was achieved by using Cu/Togni's reagent system. Not only gem-di-substituted styrenes, but also a beta-methylstyrene derivative were transformed to the corresponding oxy-trifluoromethylation products. 1,4-Addition products were obtained selectively in the reaction of mono-substituted dienes. These reactions provide a new approach for the synthesis of beta-trifluoromethyl styrene derivatives. (C) 2014 The Authors. Published by Elsevier B.V.