Dissertation Information for Bing Liu NAME: - Bing Liu
DEGREE:
- Ph.D.
DISCIPLINE:
- Chemistry
SCHOOL:
- Emory University (USA) (2000)
ADVISORS: - Albert Padwa
COMMITTEE MEMBERS: - Frank E. McDonald - Debra L. Mohler
MPACT Status: Fully Complete
Title: Application of cycloaddition and cyclization chemistry for alkaloid synthesis
Abstract: "The intermolecular Diels-Alder reaction of 2-amidofurans provides a versatile approach toward the synthesis of a variety of hydroindole ring systems. Employing this cycloaddition chemistry as the key step, the synthesis of the Amaryllidaceae alkaloids hippadine and (¡À)-crinane as well as the Dendrobium alkaloid (¡À)-dendrobine was accomplished from readily available starting materials. This strategy should be of general utility for the synthesis of more complex hydroindole alkaloids.
Cyclic 2-amidofurans can be synthesized using an intramolecular Diels-Alder reaction of 2-amino-substituted oxazoles that contain a tethered alkyne. This transformation represents a new route to this rare heterocyclic ring system. This protocol was successfully used for a formal synthesis of the pyrrolophenanthridone alkaloids hippadine and ungeremine.
The intramolecular dipolar cycloaddition of thioisom¨¹nchnones generated from N-monosubstituted thioamides and ¦Á-bromoalkenoyl chlorides represents a highly effective method for the synthesis of the core indolo[2,3- a ]quinolizidine skeleton found in yohimbine. In the case of thioamides which contain an ¦Á-hydrogen, deprotonation to form the S,N -ketene acetal proceeds much faster than formation of thioisom¨¹nchnones. A short synthesis of (¡À)-alloyohimbane using this bicycloannulation of carboline-1-thione was demonstrated to highlight the synthetic utility of thioisom¨¹nchnones in organic synthesis.
Cyclization of diazo lactams with Rh(II) catalysts was studied. The decomposition of these diazo keto-lactams with Rh(II) catalysts provides a concise approach to both indolizinone and quinolizinone skeletons through an initially formed transient epoxide. Rearrangement of the transient epoxide is highly dependent upon the substitution about the epoxide ring."
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MPACT Scores for Bing Liu A = 0
C = 0
A+C = 0
T = 0
G = 0
W = 0
TD = 0
TA = 0
calculated 2008-04-10 16:13:57
Advisors and Advisees Graph
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