title: 9-Borabicyclo[3.3.2]decanes and the asymmetric hydroboration of 1,1-disubstituted alkenes.
abstract: The syntheses of the optically pure asymmetric hydroborating agents 1 (a, R = Ph; b, R = TMS) in both enantiomeric forms are reported. These reagents are effective for the hydroboration of cis-, trans- and trisubstituted alkenes. More significantly, they exhibit unprecedented levels of selectivity in the asymmetric hydroboration of 1,1-disubstituted alkenes (28-92% ee), a previously unanswered challenge in the nearly 50 year history of this reagent-controlled process. For example, the hydroboration of alpha-methylstyrene with 1a produces the corresponding alcohol 6f in 78% ee (cf., Ipc2BH, 5% ee). Suzuki coupling of the intermediate adducts 5 produces the nonracemic products 7 very effectively (50-84%) without loss of optical purity.
authors.affiliation: University of Puerto Rico, Department of Chemistry, Rio Piedras, Puerto Rico.
authors.forename: Ana Z
authors.initials: AZ
authors.lastname: Gonzalez
authors.forename: José G
authors.initials: JG
authors.lastname: Román
authors.forename: Eduvigis
authors.initials: E
authors.lastname: Gonzalez
authors.forename: Judith
authors.initials: J
authors.lastname: Martinez
authors.forename: Jesus R
authors.initials: JR
authors.lastname: Medina
authors.forename: Karl
authors.initials: K
authors.lastname: Matos
authors.forename: John A
authors.initials: JA
authors.lastname: Soderquist
mesh_terms: D000438:Alcohols / Q000138:chemical synthesis*; D000473:Alkanes / Q000138:chemical synthesis* / Q000737:chemistry; D000475:Alkenes / Q000737:chemistry*; D001880:Boranes / Q000138:chemical synthesis* / Q000737:chemistry; D001894:Borohydrides / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D054199:Pseudoephedrine / Q000031:analogs & derivatives / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000438:Alcohols; D000473:Alkanes; D000475:Alkenes; D001880:Boranes; D001894:Borohydrides; D054199:Pseudoephedrine; C012867:decane