(PNP)Cobalt-Catalyzed Olefination of Diazoalkanes

Sam Yruegas, Scott P. Semproni, Paul J. Chirik

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Addition of excess diazoalkane to the pincer-supported cobalt(I) dinitrogen complex (tBumPNP)CoN2(tBumPNP = modified 2,6-bis[(ditert-butylphosphino)methyl]pyridine) resulted in the catalytic formation of the homocoupled alkene product with concomitant loss of N2. Monosubstituted diazoalkanes, trimethylsilyldiazomethane and tolyldiazomethane, generated the olefin product in quantitative yield with exclusive (E)-stereoselectivity. Disubstituted diazoalkanes, diphenyldiazomethane and 9-diazofluorene, also yielded the olefin as the major product along with minor azine coupling. Investigations into the nature of the diazoalkane-cobalt interaction by multinuclear NMR spectroscopy and X-ray diffraction established end-on diazoalkane cobalt complexes as the resting states. The isolated four-coordinate cobalt diazoalkane complexes promoted conversion to the corresponding olefin. The reaction of (tBumPNP)CoN2with an α-diazo-β-ketoester resulted in the formation of a five-coordinate Co(I)-diazoalkane complex with a chelating ester unit that was unreactive for olefination.

Original languageEnglish (US)
Pages (from-to)3138-3144
Number of pages7
JournalOrganometallics
Volume41
Issue number22
DOIs
StatePublished - Nov 28 2022

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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