Thesis advisor: Amir H. Hoveyda / We have developed a broadly applicable strategy for the enantioselective and diastereodivergent synthesis of unprotected α-secondary amines, secondary and tertiary alcohols from nitriles. Through a bis-phosphine–Cu-catalyzed enantioselective multicomponent allyl addition to nitriles, we generate stable β,γ-unsaturated N–H ketimines with internal C=N to B(pin) chelation. We achieved stereodivergent amine synthesis through maintaining the C=N to B(pin) chelation or disruption of this internal chelation in the ketimine intermediate throughout the reduction. In the preparation of syn-homoallylic amines, a non-productive side catalytic cycle was introduced to selectively delay the function of a competitive catalyst, making several catalysts cooperate productively. The utility of this method is demonstrated through a diastereo- and enantioselective synthesis of (+)-tangutorine in gram quantities. We have also developed the syntheses of enantiomerically enriched secondary and tertiary alcohols through diastereodivergent reduction and diastereoselective addition of a C-based nucleophile to β,γ-unsaturated ketones, prepared from hydrolysis of the aforementioned N–H ketimines. Tertiary alcohols containing two non-differentiable functional groups, are prepared with high stereoselectivity through our strategy. We demonstrated the utility of this approach by a concise preparation of a key intermediate in (+)-rubriflordilactone B synthesis. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.
| Identifer | oai:union.ndltd.org:BOSTON/oai:dlib.bc.edu:bc-ir_108926 |
| Date | January 2020 |
| Creators | Zhang, Shaochen |
| 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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