title: Enantioselective homocrotylboration of aliphatic aldehydes.
abstract: A practical route to optically pure syn-homocrotylation reagents is described, including highly diastereo- and enantioselective preparation of numerous syn-homocrotyl products, as well as several matched mismatched pairs. NMR experiments suggest that the active homocrotylating species is a cyclopropylcarbinyldichloroborane generated by chloride exchange from the PhBCl(2) activator. Computational studies support the intermediacy of chloroboranes and suggest that homoallyl/homocrotyl transfers occur through Zimmerman-Traxler transition states.
authors.affiliation: Department of Chemistry, Brandeis University, Waltham, Massachusetts 02454-9110, United States.
authors.forename: Hongkun
authors.initials: H
authors.lastname: Lin
authors.forename: Wenbo
authors.initials: W
authors.lastname: Pei
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Kendall N
authors.initials: KN
authors.lastname: Houk
authors.forename: Isaac J
authors.initials: IJ
authors.lastname: Krauss
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D001880:Boranes / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D011789:Quantum Theory; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D001880:Boranes