Stereospecific hydrohalogenation reactions of alkynes in ionic liquids

ORGN 160

Jose Salazar, jsalazar@usb.ve, Francys Fernandez, Simon Lopez, and Romano Dorta. Departamento de Quimica, Universidad Simon Bolivar, Sartenejas Baruta, Caracas, Venezuela
A series of alkynes were stereospecifically hydrohalogenated in ionic liquids using N-butylpyridinium halides/trifluoroacetic acid mixtures (1:1) at 25-70 oC , giving the corresponding halovinyl Z-isomer as the only product in moderate to high yields ( 67-97%). The reaction is highly stereospecific, solvent-free and very clean with not side-products. After completion and isolation of the product, N-butylpyridinium trifluoroacetate can be recovered as a new ionic liquid which may be reusable.