Chemistry Weekly Seminar - Mehran Rezazadeh, PhD Candidate
Mehran Rezazadeh, PhD candidate in the Department of Chemistry, will present a seminar at 1:30 pm via Zoom.
Title
Enantioselective bis(amino)cyclopropenylidene (BAC) catalysis
Abstract
The synthesis of 1,4-dicarbonyl motifs is challenging for their unusual polarity pattern. The Stetter reaction provides a direct and convergent synthetic route for constructing 1,4-dicarbonyls using a strategic C-C bond formation. There are only a few enantioselective intermolecular Stetter reaction methodologies. Only, those with highly electrophilic substrates deliver a high level of stereoselectivity. Previous studies in our lab showed that BACs are competent catalysts for the Stetter reactions with simple enones and aldehydes. A series of novel chiral BAC scaffolds were prepared and tested in this class of Stetter reactions which led to an excellent level of enantioselectivity.
The origin of the enantioselectivity observed in this reaction was explored using a DFT computational method. An intensive investigation was carried out to find plausible transition states and intermediates. Calculations showed the pathway leading to the observed R enantiomer is energetically favored for 1.0 kcal/mole, in close agreement with experimental data. These results will be discussed, along with the potential of this novel class of catalysts to be used in other carbene-catalyzed reactions.
Date: Friday, September 18, 2020
Time: 1:30 p.m.
Via Zoom video conference (link available by request to chem.dept@usask.ca)