Effect of Altering Substitution of Alkenes on Dienyne Metathesis

Although the process of ring-closing of organic compounds—metathesis—has not been a widely studied mechanism in the past, chemists today are more aware of its potential applications and the importance of studying metathesis. In field of chemistry, investigation of the metathesis mechanism has transformed both retro-synthetic planning and the reactions used to create medicinal drugs. The mechanism studied in this project, dienyne metathesis, is a modification of a standard metathesis; the standard reaction is known to produce a 1:1 ratio of tricyclic product to cyclic boronic half acid product. The objective of this study is to determine the effect of altering the substitution of the alkenes on the product ratio, and the hypothesis is that changing the substitution of the alkene in a propargyl homoallylic alcohol will affect the product ratio resulting from the metathesis of the alcohol. Specifically, the hypothesis is that increasing the substitution of the alkene next to the boron atom in a propargyl homoallylic alcohol will increase the relative amount of the tricyclic product produced by the reaction, as metathesis generally occurs at a less substituted alkene before the alkyne. Procedures for producing the propargyl alcohols necessary for metathesis were successfully developed during the course of this project. Data gathered thus far supports the hypothesis that increasing the alkene substitution of the propargyl alcohols decreases the amount of this product present after metathesis. Future work will include modifying the purification process after the metathesis reaction and repeating the reaction with different starting materials