title: Synthesis of Z-(pinacolato)allylboron and Z-(pinacolato)alkenylboron compounds through stereoselective catalytic cross-metathesis.
abstract: The first examples of catalytic cross-metathesis (CM) reactions that furnish Z-(pinacolato)allylboron and Z-(pinacolato)alkenylboron compounds are disclosed. Products are generated with high Z selectivity by the use of a W-based monoaryloxide pyrrolide (MAP) complex (up to 91% yield and >98:2 Z:E). The more sterically demanding Z-alkenylboron species are obtained in the presence of Mo-based MAP complexes in up to 93% yield and 97% Z selectivity. Z-selective CM with 1,3-dienes and aryl olefins are reported for the first time. The utility of the approach, in combination with catalytic cross coupling, is demonstrated by a concise and stereoselective synthesis of anticancer agent combretastatin A-4.
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: Elizabeth T
authors.initials: ET
authors.lastname: Kiesewetter
authors.forename: Robert V
authors.initials: RV
authors.lastname: O'Brien
authors.forename: Elsie C
authors.initials: EC
authors.lastname: Yu
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Meek
authors.forename: Richard R
authors.initials: RR
authors.lastname: Schrock
authors.forename: Amir H
authors.initials: AH
authors.lastname: Hoveyda
mesh_terms: D000475:Alkenes; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry; D001632:Bibenzyls / Q000737:chemistry; D001896:Boron Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D002074:Butanones / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003432:Cross-Linking Reagents; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013237:Stereoisomerism; D013343:Styrenes / Q000737:chemistry; D014753:Vinyl Compounds / Q000737:chemistry
chemical_list: D000475:Alkenes; D000972:Antineoplastic Agents, Phytogenic; D001632:Bibenzyls; D001896:Boron Compounds; D002074:Butanones; D003432:Cross-Linking Reagents; D007202:Indicators and Reagents; D013343:Styrenes; D014753:Vinyl Compounds; C040105:combretastatin