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Dissertation Information for Heilam Wong

NAME:
- Heilam Wong

DEGREE:
- Ph.D.

DISCIPLINE:
- Chemistry

SCHOOL:
- Emory University (USA) (2006)

ADVISORS:
- Lanny S. Liebeskind

COMMITTEE MEMBERS:
- Dennis C. Liotta
- Simon B. Blakey

MPACT Status: Fully Complete

Title: Design, synthesis and resolution of a chiral, non-racemic organometallic chiron: Asymmetric total syntheses of tetrahydropyridine based alkaloids

Abstract: An enantiopure 5-oxo-([eta]-2,3,4)-dihydropyridinyl molybdenum complex has been designed as a versatile organometallic chiron for the synthesis of piperidine based alkaloid natural products and biologically active pharmaceuticals. A scalable synthetic route starting from benzyl glycine ether ester has been developed. After installation of a chiral non-racemic ( S )-1-phenylbutoxycarbonyl protecting group, the key scaffold was successfully resolved in large quantity and in high enantiomeric excess. A series of 2,3,6-trisubstituted tetrahydropyridinyl molybdenum complexes were prepared in five steps from the platform complex. Organocerium addition of the key scaffold followed by dehydration afforded an ene-allyl complex. The key intermediate exocyclic olefin complex was synthesized efficiently through a one-pot regioseletive methoxy abstraction/nucleophilic addition/deprotonation sequence from the ene-allyl complex. A cascade protonation/organocuprate addition of the exocyclic olefin complex furnished the synthesis of 2,3,6-trisubstituted tetrahydropyridinyl molybdenum complex. The exocyclic olefin complex also underwent a novel Prins reaction initiated cascade reaction to give perhydroquinolinyl molybdenum complex. Further studies should lead to a general approach to perhydroquinoline alkaloids. The 2,3,6-trisubstituted tetrahydropyridinyl molybdenum complexes underwent reductive or proto demetallation to afford 2,6- cis -3- trans -tetrahydropyridines and 2,3,6- cis tetrahydropyridines respectively. The generality, versatility and synthetic utility of this methodology have been demonstrated by the concise total syntheses of indolizidine (±)209I, indolizidine (±)-3- epi -219F, indolizidine (-)-251N, dehydroindolizidine (-)-233E and quinolizidine (-)-251AA.

MPACT Scores for Heilam Wong

A = 0
C = 0
A+C = 0
T = 0
G = 0
W = 0
TD = 0
TA = 0
calculated 2008-02-24 22:24:45

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