Ligand-controlled cobalt-catalyzed regiodivergent hydroboration of aryl,alkyl-disubstituted internal allenes.

ABSTRACT: We report a stereoselective regiodivergent hydroboration of aryl,alkyl-disubstituted internal allenes with pinacolborane (HBpin) in the presence of cobalt catalysts generated from bench-stable Co(acac)₂ and bisphosphine ligands. An interesting correlation between the regioselectivity of this hydroboration and the bite angles of bisphosphine ligands was identified. When hydroboration was conducted with cobalt catalysts containing bisphosphines with medium bite angles (e.g. 98° for dppb and 96° for dppf), HBpin was selectively added to the alkyl-substituted double bond. However, HBpin was selectively added to the aryl-substituted double bond when the reactions were conducted with cobalt catalysts containing bisphosphines with large bite angles (e.g. 111° for xantphos

SUBMITTER: Wu C 

PROVIDER: S-EPMC8157611 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature