Final Report Summary - ABACCR (Asymmetric Brønsted Acid Catalysed Cyclisation Reactions)
The concept of our proposal is to exploit the high reactivity of N-acyl iminium ions in cyclisation reactions within the chiral environment of an associated chiral conjugate base of a Brønsted acid HA*.
Following the preliminary result published by the Dixon Group, during this project our objectives were to: A) explore the the Asymmetric Brønsted acid catalysed N-acyl iminium ion cyclisation Reacions; B) apply the reaction to the enantioselective synthesis of the indole alkaloid Subincanadine B; C) investigate new enantioselective intermolecular reactions using chiral Brønsted acids.
We have investigated and found that our previously published reaction can be extended to a wide range of enol lactone substrates bearing substituted aromatic rings in the 5-position. This work is being written up for publication.
Paper in preparation: stereoselective Brønsted acid-catalyzed N-acyliminium cyclization cascades for the synthesis of highly substituted β-carbolines Michael E. Muratore, Chloe A. Holloway, Lei Shi, R. Ian Storer and Darren J. Dixon.
We have also investigated a dual catalysis method for accessing the beta-carboline products and have found a remarkable compatibility of 3,3'-substituted binol phosphoric acids with certain polymer supported bases, attributed to a size exclusion phenomenon. This is likely to be an important finding which will have impact in a range of asymmetric catalysis programs employing binol phosphoric acids.
Paper in preparation: Size Exclusion Annihilation Resistance in Enantioselective Binol Phosphoric Acid Catalysis Michael E. Muratore, Lei Shi, R. Ian Storer and Darren J. Dixon.
During this project we made a number of attempts to synthesise the indole alkaloid Subincanadine B. Unfortunately none of these successfully made the natural product, nor the key intermediate we believed would provide us access to the natural product. However, we have succeeded to develop two methods of preparing highly functionalised β-carbolines with moderate to good stereocontrol over a quaternary stereogenic centre. In addition to these successes we also explored other new N-acyl iminium cyclisation reactions using for example tethered imidazoles and a range of intermolecular reactions using the chiral Brønsted acids as catalysts and facilitators.
Uploaded, please find the final publishable summary report.
Following the preliminary result published by the Dixon Group, during this project our objectives were to: A) explore the the Asymmetric Brønsted acid catalysed N-acyl iminium ion cyclisation Reacions; B) apply the reaction to the enantioselective synthesis of the indole alkaloid Subincanadine B; C) investigate new enantioselective intermolecular reactions using chiral Brønsted acids.
We have investigated and found that our previously published reaction can be extended to a wide range of enol lactone substrates bearing substituted aromatic rings in the 5-position. This work is being written up for publication.
Paper in preparation: stereoselective Brønsted acid-catalyzed N-acyliminium cyclization cascades for the synthesis of highly substituted β-carbolines Michael E. Muratore, Chloe A. Holloway, Lei Shi, R. Ian Storer and Darren J. Dixon.
We have also investigated a dual catalysis method for accessing the beta-carboline products and have found a remarkable compatibility of 3,3'-substituted binol phosphoric acids with certain polymer supported bases, attributed to a size exclusion phenomenon. This is likely to be an important finding which will have impact in a range of asymmetric catalysis programs employing binol phosphoric acids.
Paper in preparation: Size Exclusion Annihilation Resistance in Enantioselective Binol Phosphoric Acid Catalysis Michael E. Muratore, Lei Shi, R. Ian Storer and Darren J. Dixon.
During this project we made a number of attempts to synthesise the indole alkaloid Subincanadine B. Unfortunately none of these successfully made the natural product, nor the key intermediate we believed would provide us access to the natural product. However, we have succeeded to develop two methods of preparing highly functionalised β-carbolines with moderate to good stereocontrol over a quaternary stereogenic centre. In addition to these successes we also explored other new N-acyl iminium cyclisation reactions using for example tethered imidazoles and a range of intermolecular reactions using the chiral Brønsted acids as catalysts and facilitators.
Uploaded, please find the final publishable summary report.
