Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)
Narome Belus - University of the Virgin Islands
Co-Author(s): Emily R. Lutz
BINOL-silenediols are a class of stereoselective catalyst, used to speed up the process of an organic reaction. In the addition reaction of indole to arylidene malonate, silanediol is used in conjunction with the anion, copper (II) triflate, to yield an optically active product. The best result obtained from this reaction was a 99% yield and 49% enantiomer excess (ee), which was done with the conditions of -27°C using the solvent toluene. The purpose of this research was to understand the mechanistic pathway for the addition reaction to further obtain a higher ee. This addition reaction can proceed in two different pathways: (1) silanediol acts as a catalyst by going through anion binding with triflate, (2) silanediol binds as a ligand to the copper compound. In order to determine the specific pathway for this addition reaction, various experimental processes were conducted using different laboratory instruments. The in-situ react IR studies showed that the silanediol interacted with triflate in tert-butyl ammonium triflate in a 1:1 ratio which proved that hydrogen bonding occurred. However, in the reaction with silanediol and copper (II) triflate there is a 2:1 ratio observed which suggested possible interaction between silanediol and copper. Additionally, ES-IMS data showed that in the reaction with silanediol and copper (II) triflate a compound complex forms, which consisted of two copper molecules and a silanediol compound. For the react IR studies however, it was observed that when the mixture is heterogeneous the IR would not detect any interaction. Further solubility studies were then conducted to find a solvent that dissolved every reactant and gave a high percentage yield and ee. These studies showed that this reaction have to be synthesized under heterogeneous conditions. Overall, these instrumental studies suggest that both mechanistic pathways for this reaction are possible, but it is nearly impossible to breakdown and understand the mechanism of this heterogeneous reaction.Not Submitted
Funder Acknowledgement(s): Funded by the National Science Foundation (NSF)
Faculty Advisor: Anita Mattson, firstname.lastname@example.org
Role: I read articles and ran the experiments using different instruments such as the H'NMR, HPLC, React-IR and ES-IMS.