Total Synthesis of (+)-Hyperaspine, Advances Toward the Total Synthesis of Spirolucidine, and [2+2]-Photochemical Cycloadditions of 2,3-Dihydro-4-Pyridones

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dc.contributor.advisor Dr. Daniel Lee Comins, Committee Chair en_US
dc.contributor.advisor Dr. Alex Deiters, Committee Member en_US
dc.contributor.advisor Dr. Bruce Novak, Committee Member en_US
dc.contributor.advisor Dr. Christian Melander, Committee Member en_US
dc.contributor.author Sahn, James Jeffrey en_US
dc.date.accessioned 2010-04-02T19:15:31Z
dc.date.available 2010-04-02T19:15:31Z
dc.date.issued 2009-01-05 en_US
dc.identifier.other etd-12182008-133301 en_US
dc.identifier.uri http://www.lib.ncsu.edu/resolver/1840.16/5539
dc.description.abstract The ladybug alkaloid, (+)-hyperaspine, was synthesized in 6 steps and 21% overall yield. Utilizing Cs2CO3 and CH2Br2, a novel entry into the 3,4,4a,5-tetrahydropyrido[1,2-c][1,3]oxazin-6(1H)-one ring system was developed. The synthesis showcases a stereoselective dissolving-metal reduction, which provided the requisite equatorial alcohol that was rapidly advanced to the natural product. Significant progress has been made towards the total synthesis of the Lycopodium alkaloid, spirolucidine. Implementing a convergent approach to the natural product, zone A was synthesized and united with zone B. Subsequent elaboration of the A-B fragment afforded the N-Boc derivative for an impending ortho-lithiation. Additionally, the racemic, desmethyl zone C was prepared from its carboxylic acid precursor via the Barton ester. Finally, the Negishi cross-coupling reaction was investigated for the union of racemic, desmethyl zone C with a zone B surrogate. The intramolecular [2+2]-photochemical cycloaddition of 2,3-dihydro-4-pyridones proceeded in good yield with excellent stereocontrol. When the photoadducts were treated with SmI2, different mechanistic pathways ensued. The lower homologue underwent a dual ring opening/reduction, rendering a cis 2,6-disubstituted piperidinol. Exposure of the higher homologue to SmI2 resulted in homolytic β-cleavage, which afforded an azaspiro[5.5]undecane. en_US
dc.rights I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dis sertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. en_US
dc.subject samarium diiodide en_US
dc.subject dihydropyridone en_US
dc.subject hyperaspine en_US
dc.subject spirolucidine en_US
dc.subject 2+2 en_US
dc.subject photocycloaddition en_US
dc.subject azaspiro en_US
dc.title Total Synthesis of (+)-Hyperaspine, Advances Toward the Total Synthesis of Spirolucidine, and [2+2]-Photochemical Cycloadditions of 2,3-Dihydro-4-Pyridones en_US
dc.degree.name PhD en_US
dc.degree.level dissertation en_US
dc.degree.discipline Chemistry en_US


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