Towards the total synthesis of Daphniyunnine B
This thesis describes the development of a series of synthetic routes towards the first synthesis of Daphniyunnine B, a Daphniphyllum alkaloid, utilising novel reactions and cascades. Studies began with an envisaged enantioselective Michael cascade reaction, which alternatively gave rise to a novel,...
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University of Manchester
2010
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| Online Access: | http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525928 |
| Summary: | This thesis describes the development of a series of synthetic routes towards the first synthesis of Daphniyunnine B, a Daphniphyllum alkaloid, utilising novel reactions and cascades. Studies began with an envisaged enantioselective Michael cascade reaction, which alternatively gave rise to a novel, efficient Michael-aldol cascade reaction affording perhydroindole structures in moderate to excellent diastereoselectivity. The enantioselective synthesis of the methyl-substituted core of Daphniyunnine B was achieved via an initial highly enantioselective organocatalytic Michael addition followed by a stereoselective organocatalytic intramolecular Michael addition.The stereocontrolled synthesis of the AC bicyclic core of (±) Daphniyunnine B was achieved via a quaternisation cyclisation approach.The stereo controlled synthesis of the ACD tricyclic core of (±) Daphniyunnine B was achieved via an intramolecular Diels-Alder fragmentation reaction. Preliminary studies of an enantioselective variant are encouraging. |
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