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Diverse functionalization of strong alkyl C-H bonds by undirected borylation.

ABSTRACT: The selective functionalization of strong, typically inert carbon-hydrogen (C-H) bonds in organic molecules is changing synthetic chemistry. However, the undirected functionalization of primary C-H bonds without competing functionalization of secondary C-H bonds is rare. The borylation of alkyl C-H bonds has occurred previously with this selectivity, but slow rates required the substrate to be the solvent or in large excess. We report an iridium catalyst ligated by 2-methylphenanthroline with activity that enables, with the substrate as limiting reagent, undirected borylation of primary C-H bonds and, when primary C-H bonds are absent or blocked, borylation of strong secondary C-H bonds. Reactions at the resulting carbon-boron bond show how these borylations can lead to the installation of a wide range of carbon-carbon and carbon-heteroatom bonds at previously inaccessible positions of organic molecules.

SUBMITTER: Oeschger R

PROVIDER: S-EPMC7710342 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature

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Diverse functionalization of strong alkyl C-H bonds by undirected borylation.

Oeschger Raphael R Su Bo B Yu Isaac I Ehinger Christian C Romero Erik E He Sam S Hartwig John J

Science (New York, N.Y.) 20200501 6492

The selective functionalization of strong, typically inert carbon-hydrogen (C-H) bonds in organic molecules is changing synthetic chemistry. However, the undirected functionalization of primary C-H bonds without competing functionalization of secondary C-H bonds is rare. The borylation of alkyl C-H bonds has occurred previously with this selectivity, but slow rates required the substrate to be the solvent or in large excess. We report an iridium catalyst ligated by 2-methylphenanthroline with ac ...[more]

PMID: 32409470

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