Catalytic Cycloisomerization onto a Carbonyl Oxygen
| Autor: | Tao Chen, Jonathan L. Kuo, Shicheng Shi, Jack R. Norton |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Radical
010402 general chemistry Ring (chemistry) 01 natural sciences Biochemistry Medicinal chemistry Article Catalysis chemistry.chemical_compound Cycloisomerization Isomerism Molecule Physical and Theoretical Chemistry Molecular Structure 010405 organic chemistry Chemistry Organic Chemistry Hydrogen atom Silanes Silane 0104 chemical sciences Oxygen Cyclization Isomerization Hydrogen |
| Zdroj: | Org Lett |
| ISSN: | 1523-7052 1523-7060 |
| DOI: | 10.1021/acs.orglett.0c02272 |
| Popis: | We have found that terminal N-vinylindoles bearing cycloalkanone substituents are excellent hydrogen atom acceptors, generating α-aminyl radicals with a variety of catalysts (Co(II)/H(2) or Co(III)Cl precatalysts with silane reductants). These radicals can be converted to internal vinylindoles but eventually add to the oxygen of the cycloalkanone substituents. These cyclizations eventually furnish a densely functionalized dihydrofuran (a net cycloisomerization). The internal vinylindoles are slowly converted to the dihydrofurans, but the final cycloisomerization/isomerization ratio is affected by the size of the cycloalkanone ring (seven- and eight-membered rings give the highest ratio). These results demonstrate how HAT can isomerize substrates in nonintuitive ways, here leading to the first HAT-promoted formation of a C–O bond. |
| Databáze: | OpenAIRE |
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