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Title: The synthesis and resolution of a new chiral auxiliary and its application in asymmetric dihydroxylation, and, The first total synthesis of (+)-allomatrine and other lupin alkaloids
Author: Watkin, Samuel
ISNI:       0000 0004 2743 0705
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 2013
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The synthesis and resolution of a new chiral auxiliary; trans-2-tritylcyclohexanol (1.15) is described allowing access to either enantiomer in gram quantities in excellent enantiomeric purity; (−)-1.15 in >99% ee and (+)-1.15 in 97% ee. Our new chiral controller (1.15) was subsequently applied to the diastereoselective osmium catalysed dihydroxylation of its 2-substituted acrylate ester derivatives. (±)-1.15 exhibited improved selectivity over other chiral auxiliary controlled dihydroxylations of substituted acrylate esters. In addition, the first total synthesis of the tetracyclic lupin alkaloid (+)-allomatrine (5.01) has been completed in 6% yield over 12 steps. This was followed by a second generation synthesis improving on our previous efforts; increasing the overall yield to 14%. The target molecule was assembled with excellent control of four contiguous stereocentres employing a diastereoselective imino-aldol reaction, ring-closing metathesis and an N-acyliminium cyclisation as key transformations. As part of our studies towards (+)-allomatrine (5.01) we performed the first total synthesis of the unnatural isomeric tricyclic alkaloid; (−)-lamprolobine (6.14) and bicyclic lupin alkaloid (−)-epilupinine (5.62).
Supervisor: Brown, Richard Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QC Physics