title: Highly selective allylborations of aldehydes using α,α-disubstituted allylic pinacol boronic esters.
abstract: α,α-Disubstituted allylic pinacol boronic esters undergo highly selective allylborations of aldehydes to give tetrasubstituted homoallylic alcohols with exceptional levels of anti-Z-selectivity (>20:1). The scope of the reaction includes both acyclic and cyclic allylic boronic esters which lead to acyclic and exocyclic tetrasubstituted homoallylic alcohols. The use of β-borylated allylic boronic esters gave fully substituted alkenes bearing a boronic ester which underwent further cross-coupling enabling a highly modular and stereoselective approach to the synthesis of diaryl tetrasubstituted alkenes. Computational analysis revealed the origin of the remarkable selectivity observed.
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS (UK) http://www.bris.ac.uk/chemistry/research/organic/aggarwal-group.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Hesse
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Essafi
authors.forename: Charlotte G
authors.initials: CG
authors.lastname: Watson
authors.forename: Jeremy N
authors.initials: JN
authors.lastname: Harvey
authors.forename: David
authors.initials: D
authors.lastname: Hirst
authors.forename: Christine L
authors.initials: CL
authors.lastname: Willis
authors.forename: Varinder K
authors.initials: VK
authors.lastname: Aggarwal
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000475:Alkenes / Q000138:chemical synthesis*; D001895:Boron / Q000737:chemistry*; D004952:Esters / Q000737:chemistry*; D015394:Molecular Structure
chemical_list: D000447:Aldehydes; D000475:Alkenes; D004952:Esters; D001895:Boron
keywords: CC coupling; alkenes; allylation; asymmetric synthesis; synthetic methods