Previous studies of the rhodium trichloride (RhCl3) catalyzed hydroboration mechanisms of alkenes showed rearrangements and unusual regiochemistry compared to simple uncatalyzed hydroboration, and complex mechanisms have been proposed to explain these results. Earlier studies suggested that isomerization of alkenes in the presence of RI1CI3 prior to hydroboration accounted for these results. Studies of alkene rearrangements in the presence of RI1CI3 also suggest that the results are due to a different mechanism. The elimination-addition promoted elimination of R-Rh-B structures was shown to be responsible for isomerization and formation of different alcohol isomers after hydroboration. These interesting results prompted us to study the hydroboration reactions of alkenes with functional groups in the presence of RI1CI3. Previous studies on the uncatalyzed hydroboration reactions of alkenes with functional groups showed that the presence of substituents can introduce marked directive influences on the hydroboration reaction. In the case of alkenyl chlorides this is followed by elimination reactions. Hydroboration reaction of alkenyl nitriles has been studied for the first time in this work in detail. The presence of RI1CI3 exerted a profound effect upon the hydroboration reactions of alkenyl nitriles and alkenyl chlorides. RI1CI3 mainly served to reduce this substituent effect and to isomerize the elimination products. An unexpected processtrimerization reaction of acetonitrile has also been observed from the result of carboncarbon bond breaking in allyl cyanide. The mechanism of this process has been studied in detail. Alkenyl chlorides favored the formation of racemic mixtures of chiral compounds in the presence of rhodium trichloride. In addition to that the effect of temperature on the hydroboration of alkenyl nitriles and chloride has been studied for the first time
