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Towards the total synthesis of (-)-sparteine and other lupin alkaloids & new chiral catalysts for asymmetric epoxidations

Towards the total synthesis of (-)-sparteine and other lupin alkaloids & new chiral catalysts for asymmetric epoxidations
Towards the total synthesis of (-)-sparteine and other lupin alkaloids & new chiral catalysts for asymmetric epoxidations
Synthetic routes towards the total synthesis of (?)-sparteine (1.1) have been investigated. An imino-aldol reaction between different ester enolates and chiral sulfinimines was explored to install two of the stereogenic centres. An N-acylimnium precursor was introduced from a selective imide reduction with LiEt3BH and several cyclisation strategies were investigated to install the two remaining stereocenters. Total synthesis of the bicyclic lupin alkaloid (?) lamprolobine (1.107) has been completed in 21% yield over 12 steps as part of the synthetic studies towards 1.1. The target molecule was assembled using a diastereoselective imino aldol reaction and radical deoxygenation as key transformations in the synthesis. The stereochemistry of the major syn product of the imino-aldol reaction was confirmed by single crystal X-ray crystallography. In addition to this, several chiral acyclic ?-ketoamides and cyclic ?-ketoamides have been synthesised and evaluated in ketone mediated epoxidation of olefins. Despite the modest enantiomeric excesses (ee < 10%) achieved, it was shown that these ?- ketocarboxylic acid derivatives are capable of efficient epoxidation at low catalyst loadings.
University of Southampton
Pop, Ionut-Alexandru
fb310398-c5e3-4942-96de-a95354adafc4
Pop, Ionut-Alexandru
fb310398-c5e3-4942-96de-a95354adafc4
Brown, Richard
21ce697a-7c3a-480e-919f-429a3d8550f5

Pop, Ionut-Alexandru (2015) Towards the total synthesis of (-)-sparteine and other lupin alkaloids & new chiral catalysts for asymmetric epoxidations. University of Southampton, Chemistry, Doctoral Thesis, 253pp.

Record type: Thesis (Doctoral)

Abstract

Synthetic routes towards the total synthesis of (?)-sparteine (1.1) have been investigated. An imino-aldol reaction between different ester enolates and chiral sulfinimines was explored to install two of the stereogenic centres. An N-acylimnium precursor was introduced from a selective imide reduction with LiEt3BH and several cyclisation strategies were investigated to install the two remaining stereocenters. Total synthesis of the bicyclic lupin alkaloid (?) lamprolobine (1.107) has been completed in 21% yield over 12 steps as part of the synthetic studies towards 1.1. The target molecule was assembled using a diastereoselective imino aldol reaction and radical deoxygenation as key transformations in the synthesis. The stereochemistry of the major syn product of the imino-aldol reaction was confirmed by single crystal X-ray crystallography. In addition to this, several chiral acyclic ?-ketoamides and cyclic ?-ketoamides have been synthesised and evaluated in ketone mediated epoxidation of olefins. Despite the modest enantiomeric excesses (ee < 10%) achieved, it was shown that these ?- ketocarboxylic acid derivatives are capable of efficient epoxidation at low catalyst loadings.

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Published date: 26 January 2015
Organisations: University of Southampton, Chemistry

Identifiers

Local EPrints ID: 374680
URI: http://eprints.soton.ac.uk/id/eprint/374680
PURE UUID: 365c6d3d-5875-49ea-b22a-cca00fd90c06
ORCID for Richard Brown: ORCID iD orcid.org/0000-0003-0156-7087

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Date deposited: 09 Mar 2015 11:28
Last modified: 25 Oct 2019 04:01

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Contributors

Author: Ionut-Alexandru Pop
Thesis advisor: Richard Brown ORCID iD

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