Previous studies of the rhodium trichloride (RhCl3) catalyzed hydroboration of 1- octene showed a reversal of regiochemistry compared to the uncatalyzed reaction, and a complex mechanism was proposed to explain this phenomenon. Recent advances in analytical technique has revealed the presence of 4-octanol and 3-octanol. in addition to the expected 2-octanol and 1 -octanol products. The existence of these unexpected products has been attributed to the isomerization of 1-octene to internal isomers prior to normal hydroboration and oxidation, instead of the previously proposed mechanism. Initial kinetic studies indicated that the RI1CI3 catalyzed isomerization of 1-octene occurs too slowly to account for the high levels of isomerized octanols found when a full hydroboration and oxidation is performed. Further research indicates that two distinct species are responsible for the isomerization process. Rhodium trichloride itself is believed to isomerize 1-octene via the 71-allyl mechanism, and RhHCh, a proposed species resulting from reaction with borane (BH3), which isomerizes 1-octene via a Rh-H insertion into the double bond followed by P-hydride elimination. Additionally, previous research indicated the presence of Aliquat 336 (trioctylmethylammonium chloride) was necessary for the reaction to occur, while current studies have shown that while Aliquat 336 is not necessary to produce octanol products, its presence influences the relative amounts of the octanol isomers produced.
Library of Congress Subject Headings
Hydroboration; Rhodium catalysts; Octyl alcohol
Department, Program, or Center
School of Chemistry and Materials Science (COS)
Sampognaro, Anthony, "Rhodium trichloride catalyzed hydroboration of 1-octene: Unexpected results" (2000). Thesis. Rochester Institute of Technology. Accessed from
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