Research Fellows Directory
Dr Ganesh Venkataraman
University of Bristol
The philosophy of the present work centers on the development of catalytic enantioselective reaction in a completely atom-economical fashion using small molecule pronucleophiles with low acidity. Acetonitrile is one such challenging pronucleophiles (pKa= 31) that is being actively studied in the group. The use of alkylnitriles as pronucleophiles is hampered due to their low acidity to generate alpha-cyano carbanions in a catalytic manner. Our findings on the direct catalytic addition of alkylnitriles to aldehydes enabled an atom-economical access to beta-hydroxynitriles under proton transfer conditions. A transition metal/N-heterocyclic carbene (NHC) complex of rhodium and an imidazolium-based carbene was identified as an effective catalyst to promote the reaction with as little as 1.25 mol% of catalyst loading.
An enantioselective version of cyanomethylation reaction by extensive screening of chiral NHCs with varying steric and electronic characteristics with Rh(I) salts is under development. Our preliminary results show that the NHCs derived from chiral triazolium salt rendered up to 68% enantioselectivity using the present catalyst system (Rh(I)/NHC). The fine-tuning of the catalyst environment for higher enantio- and diastereoselective cyanoalkylation and the mechanistic studies on the transformation are in progress.
Interests and expertise (Subject groups)