Diastereoselective α-Alkylation of Chiral β-Borylated Esters

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dc.contributor.authorPerfetti, Michael Thomasen
dc.contributor.committeechairSantos, Webster L.en
dc.contributor.committeememberGibson, Harry W.en
dc.contributor.committeememberCarlier, Paul R.en
dc.contributor.departmentChemistryen
dc.date.accessioned2014-03-14T20:30:11Zen
dc.date.adate2010-01-13en
dc.date.available2014-03-14T20:30:11Zen
dc.date.issued2009-12-09en
dc.date.rdate2010-01-13en
dc.date.sdate2010-01-05en
dc.description.abstractThe use of boron in the synthesis and development of asymmetric methodologies and various biological and medicinal compounds has increased significantly over the last decade. This thesis reports the development of a novel diastereoselective reaction for the α-alkylation of chiral β-borylated esters. We propose that standard deprotonation of chiral β-borylated esters with lithium diisopropylamide (LDA) leads to the formation of a boron"ate" intermediate that upon treatment with an alkylation reagent collapses to provide chiral α, β-substituted boronic esters with a high degree of diastereoselectivity. This reaction is powerful in that a wide range of chiral β-borylated ester substrates can be employed that possess varying degrees of substitution and steric bulk. Results show that the reaction is syn-selective and provides yields of up to 60%, with diastereomeric ratios as high as (9.7:1). Additionally, alkylation products from bulkier tert-butyl esters provide higher DR values compared to those of methyl esters that possess the same β-functional groups. Several techniques were utilized to elucidate the mechanism of this reaction including variations of reaction temperature and equivalents of base, and also real-time analysis of the reaction by ¹¹B NMR experiments.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-01052010-184710en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-01052010-184710/en
dc.identifier.urihttp://hdl.handle.net/10919/30820en
dc.publisherVirginia Techen
dc.relation.haspartPerfetti_MT_T_2009.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectDiastereoselective α-alkylationen
dc.subjectsyn selectiveen
dc.subject11B NMRen
dc.subjectboron-"ate"en
dc.subjectβ-boronic esteren
dc.titleDiastereoselective α-Alkylation of Chiral β-Borylated Estersen
dc.typeThesisen
thesis.degree.disciplineChemistryen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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