Thesis advisor: Marc L. Snapper / Chapter 1 Bisphosphine monoxides have unique coordinating capabilities with transition metals. Several research groups have independently reported transition metal-catalyzed highly stereoselective reactions by using chiral bisphosphine monoxides as the ligands. A review of recent works in this field is provided in this chapter to showcase the features of this class of ligand. Chapter 2 We have developed a copper-catalyzed borylation method to synthesize α-aminoboronic esters, which are biologically interesting molecules in enzyme inhibitions. Employment of hemiaminal ethers as substrates to in situ generate the corresponding aldimines obviated purification of the unstable aldimines and potential imine-enamine tautomerization. By using a chiral bisphosphine monoxide ligand in our copper-catalyzed borylation conditions, we successfully synthesized a variety of enantioenriched alkyl-substituted α-aminoboronic esters in good yields and with good enantioselectivity. Chapter 3 A ruthenium-catalyzed three-step tandem sequence was established to prepare nitrogen-protected 2,3-dihydroxypyrrolidines and 2,3-dihydroxypiperidines. This tandem sequence includes ring-closing metathesis, olefin isomerization and olefin dihydroxylation, and utilizes the second-generation Grubbs’ catalyst as the initial ruthenium precatalyst. Readily accessible nitrogen-tethered dienes were used as the substrates to prepare the heterocyclic compounds in an efficient fashion. Through optimization, we discovered the optimal conditions for ruthenium-catalyzed dihydroxylation of ene-carbamates and ene-sulfonamides, which were the challenging substrates in the previous methods. / Thesis (PhD) — Boston College, 2016. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.
| Identifer | oai:union.ndltd.org:BOSTON/oai:dlib.bc.edu:bc-ir_107234 |
| Date | January 2016 |
| Creators | Xiao, Lu |
| Publisher | Boston College |
| Source Sets | Boston College |
| Language | English |
| Detected Language | English |
| Type | Text, thesis |
| Format | electronic, application/pdf |
| Rights | Copyright is held by the author, with all rights reserved, unless otherwise noted. |
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