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Insertion of CO₂ Mediated by a (Xantphos)Ni^I -Alkyl Species.

ABSTRACT: The incorporation of CO₂ into organometallic and organic molecules represents a sustainable way to prepare carboxylates. The mechanism of reductive carboxylation of alkyl halides has been proposed to proceed through the reduction of Ni^II to Ni^I by either Zn or Mn, followed by CO₂ insertion into Ni^I -alkyl species. No experimental evidence has been previously established to support the two proposed steps. Demonstrated herein is that the direct reduction of (tBu-Xantphos)Ni^II Br₂ by Zn affords Ni^I species. (tBu-Xantphos)Ni^I -Me and (tBu-Xantphos)Ni^I -Et complexes undergo fast insertion of CO₂ at 22 °C. The substantially faster rate, relative to that of Ni^II complexes, serves as the long-sought-after experimental support for the proposed mechanisms of Ni-catalyzed carboxylation reactions.

SUBMITTER: Diccianni JB

PROVIDER: S-EPMC8905775 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

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Insertion of CO2 Mediated by a (Xantphos)NiI -Alkyl Species.

Diccianni Justin B JB Hu Chunhua T CT Diao Tianning T

Angewandte Chemie (International ed. in English) 20190814 39

The incorporation of CO2 into organometallic and organic molecules represents a sustainable way to prepare carboxylates. The mechanism of reductive carboxylation of alkyl halides has been proposed to proceed through the reduction of NiII to NiI by either Zn or Mn, followed by CO2 insertion into NiI -alkyl species. No experimental evidence has been previously established to support the two proposed steps. Demonstrated herein is that the direc ...[more]

PMID: 31309669

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