title: Alkoxyboration: ring-closing addition of B-O σ bonds across alkynes.
abstract: For nearly 70 years, the addition of boron-X σ bonds to carbon-carbon multiple bonds has been employed in the preparation of organoboron reagents. However, the significantly higher strength of boron-oxygen bonds has thus far precluded their activation for addition, preventing a direct route to access a potentially valuable class of oxygen-containing organoboron reagents for divergent synthesis. We herein report the realization of an alkoxyboration reaction, the addition of boron-oxygen σ bonds to alkynes. Functionalized O-heterocyclic boronic acid derivatives are produced using this transformation, which is mild and exhibits broad functional group compatibility. Our results demonstrate activation of this boron-O σ bond using a gold catalysis strategy that is fundamentally different from that used previously for other boron addition reactions.
authors.affiliation: Department of Chemistry, University of California, Irvine , Irvine, California 92617-2025, United States.
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Hirner
authors.forename: Darius J
authors.initials: DJ
authors.lastname: Faizi
authors.forename: Suzanne A
authors.initials: SA
authors.lastname: Blum
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D001895:Boron / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010100:Oxygen / Q000737:chemistry*
chemical_list: D000480:Alkynes; D001895:Boron; D010100:Oxygen