Catalytic Cycloisomerization onto a Carbonyl Oxygen

Shicheng Shi, Jonathan L. Kuo, Tao Chen, Jack R. Norton

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

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)/H2 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.

Original languageEnglish (US)
Pages (from-to)6171-6176
Number of pages6
JournalOrganic Letters
Volume22
Issue number15
DOIs
StatePublished - Aug 7 2020

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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