title: Facile Arylation of Four-Coordinate Boron Halides by Borenium Cation Mediated Boro-desilylation and -destannylation.
abstract: The addition of AlCl3to four-coordinate boranes of the general formula (C-N-chelate)BCl2results in halide abstraction and formation of three-coordinate borenium cations of the general formula [(C-N-chelate)BCl]+. The latter react with both arylstannanes and arylsilanes by boro-destannylation and -desilylation, respectively, to form arylated boranes. Catalytic quantities of AlCl3were sufficient to effect high-yielding arylation of (C-N-chelate)BCl2. Boro-destannylation is more rapid than boro-desilylation and leads to double arylation at the boron center, whereas in reactions with arylsilanes either single or double arylation occurs dependent on the nucleophilicity of the arylsilane and on the electrophilicity of the borenium cation. The electrophilicity of the borenium cation derived from 2-phenylpyridine was greater than that of the benzothiadiazole analogues, enabling the boro-desilyation of less nucleophilic silanes and the direct electrophilic borylation of 2-methylthiophene.
authors.affiliation: School of Chemistry, University of Manchester , Manchester M13 9PL, United Kingdom.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Crossley
authors.affiliation: School of Chemistry, University of Manchester , Manchester M13 9PL, United Kingdom.
authors.forename: Jessica
authors.initials: J
authors.lastname: Cid
authors.affiliation: School of Chemistry, University of Manchester , Manchester M13 9PL, United Kingdom.
authors.forename: Liam D
authors.initials: LD
authors.lastname: Curless
authors.affiliation: School of Chemistry, University of Manchester , Manchester M13 9PL, United Kingdom.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Turner
authors.affiliation: School of Chemistry, University of Manchester , Manchester M13 9PL, United Kingdom.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Ingleson