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Terminal Alkyne Coupling Reactions through a Ring: Mechanistic Insights and Regiochemical Switching.

ABSTRACT: The mechanism and selectivity of terminal alkyne coupling reactions promoted by rhodium(I) complexes of NHC-based CNC pincer ligands have been investigated. Synthetic and kinetic experiments support E- and gem-enyne formation through a common reaction sequence involving hydrometallation and rate-determining C-C bond reductive elimination. The latter is significantly affected by the ligand topology: Employment of a macrocyclic variant enforced exclusive head-to-head coupling, contrasting the high selectivity for head-to-tail coupling observed for the corresponding acyclic pincer ligand.

SUBMITTER: Storey CM

PROVIDER: S-EPMC6175324 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature

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Terminal Alkyne Coupling Reactions through a Ring: Mechanistic Insights and Regiochemical Switching.

Storey Caroline M CM Gyton Matthew R MR Andrew Rhiann E RE Chaplin Adrian B AB

Angewandte Chemie (International ed. in English) 20180820 37

The mechanism and selectivity of terminal alkyne coupling reactions promoted by rhodium(I) complexes of NHC-based CNC pincer ligands have been investigated. Synthetic and kinetic experiments support E- and gem-enyne formation through a common reaction sequence involving hydrometallation and rate-determining C-C bond reductive elimination. The latter is significantly affected by the ligand topology: Employment of a macrocyclic variant enforced exclusive head-to-head coupling, contrasting the high ...[more]

PMID: 30004163

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