2019 Fiscal Year Annual Research Report
Synthesis of Lactones and Amino Acids via Reductive Carboxylation Reactions
| Project/Area Number |
18K05099
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| Research Institution | The University of Tokyo |
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Principal Investigator |
ユー ウージン 東京大学, 大学院理学系研究科(理学部), 特任講師 (70626077)
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| Project Period (FY) |
2018-04-01 – 2020-03-31
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| Keywords | Carbon Dioxide / Multi-Component Coupling / Lactone / Lactam / Organofluorine |
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| Outline of Annual Research Achievements |
The goal of this grant proposal was to develop multi-component and/or multi-step coupling reactions with carbon dioxide as a key component to synthesize complex organic molecules. We demonstrated that 1,1-difluoroalkenes could undergo fluorocarboxylation reactions to furnish α-trifluoromethyl carboxylic acids in excellent yields. This synthetic protocol was superior to previous methods in that we were able to shorten the synthetic route to access these valuable molecules and avoided the use of expensive fluorinating reagents.
Moreover, we developed a copper- and silver-catalyzed reductive carboxylation reaction of propargyl alcohols and amines to furnish γ-lactones and lactams in good yields. The key for this transformation was the use of Red-Al as a reducing agent can could undergo a distal trans-hydrometallation process to furnish the key organoalanate intermediate. Furthermore, we demonstrated the synthetic utility of this reaction by preparing an enantiopure natural product.
Finally, we have preliminary results (unoptimized) that shows 1,2-oxaborinan-3-enes, derived from the allylation of allylic-gem-diboronate esters and aldehydes, can undergo copper-catalyzed carboxylation reactions to furnish δ-lactones.
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