The development and applications of unsymmetrical diboron compounds
| dc.contributor.author | Guo, Xi | en |
| dc.contributor.committeechair | Santos, Webster L. | en |
| dc.contributor.committeemember | Etzkorn, Felicia A. | en |
| dc.contributor.committeemember | Kingston, David G. I. | en |
| dc.contributor.committeemember | Tanko, James M. | en |
| dc.contributor.department | Chemistry | en |
| dc.date.accessioned | 2016-06-22T06:00:24Z | en |
| dc.date.available | 2016-06-22T06:00:24Z | en |
| dc.date.issued | 2014-12-29 | en |
| dc.description.abstract | Organoboron compounds have shown a wide variety of applications in both organic synthesis and the pharmaceutical field in the past decades. Transition metal-catalyzed boration of unsaturated compounds has been studied extensively as an efficient method to install C-B bonds. Most of the previous examples employed symmetrical diboron reagents such as B₂(pin)₂ (pin = pinacolate) and B₂(cat)₂ (cat = catecholate). There are, however, limited examples of boration using unsymmetrical diboron reagents. This dissertation discloses two transition metal-catalyzed borations of unsaturated compounds with unsymmetrical diboron compounds. A Cu-catalyzed β-boration of electrophilic allenoates with a novel sp²-sp³ hybridized diboron reagent (PDIPA) is described. This unsymmetrical diboron reagent is preactivated and allows the boration to go smoothly under mild reaction conditions. The reaction provides β-borylated β,γ- unsaturated esters with exclusive (Z)-double bond geometry. These borylated products are useful intermediates for subsequent Suzuki-Miyaura cross-coupling reaction. In order to install two C-B bonds in one reaction, a Pt-catalyzed diboration of allenes with a differentially protected diboron reagent (PDAN) is presented. This unsymmetrical diboron reagent is prepared from the sp²-sp³ hybridized diboron compound, and it reacts with a series of 1,1- disubstituted allenes chemo- and regioselectively. Steric control ensures that both boryl moieties add to the terminal double bond, and the pinacol boronate preferentially attaches to the sp-hybridized carbon. The bis-boronyl products can be further converted to other functional groups as well as cross-coupling reactions. A collaborative project with Department of Physics and Department of Chemical Engineering is also discussed. In this project, a series of 𝑜-nitrobenzyl ligands containing a disulfide group as the anchor to gold surfaces are synthesized. The 𝑜-nitrobenzyl group uncages an amine upon photoexcitation. Attempts to make a water soluble analog failed, however, the mixture of methanol and water as the solvent was sufficient to attach them on gold surfaces. | en |
| dc.description.degree | Ph. D. | en |
| dc.format.medium | ETD | en |
| dc.identifier.other | vt_gsexam:4177 | en |
| dc.identifier.uri | http://hdl.handle.net/10919/71393 | en |
| dc.publisher | Virginia Tech | en |
| dc.rights | In Copyright | en |
| dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
| dc.subject | diboron compounds | en |
| dc.subject | conjugate addition | en |
| dc.subject | diboration | en |
| dc.subject | o-nitrobenzyl ligands | en |
| dc.title | The development and applications of unsymmetrical diboron compounds | en |
| dc.type | Dissertation | en |
| thesis.degree.discipline | Chemistry | en |
| thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
| thesis.degree.level | doctoral | en |
| thesis.degree.name | Ph. D. | en |