IN-SITU GENERATION AND HECK COUPLING OF ALKENES IN SUPERHEATED WATER

A series of 1,3-difunctionalized ethane derivatives were reacted with iodobenzene in the presence of PdCl2 or Pd(OAc)(2) and NaOAc in superh eated water (260 degrees C). The phenyl derivatives, 2-phenylethanol, 1-bromo-2-phenylethane, and 2-phenylethyl acetate, generated styrene w hich then coupled to the iodobenzene to form stilbene. The bromo deriv atives, 1,2-dibromoethane, 1-bromo-2-chloroethane, 2-bromoethyl acetat e, and 2-bromoethanol, lost bromide to form the respective vinyl compo unds. With the exception of the vinyl alcohol which tautomerized to ac etaldehyde, these also coupled to iodobenzene. Bromoethane did not cou ple under these conditions. The alcohol derivatives, ethanol, 2-chloro ethanol, 2-chloroethyl acetate, ethylene glycol, ethylene glycol monoa cetate, and ethylene glycol diacetate proved to be more inert under th ese relatively mild reaction conditions (260 degrees C water) and did not generate alkenes or undergo coupling to iodobenzene.