title: Catalytic asymmetric synthesis of alkynyl aziridines: both enantiomers of cis-aziridines from one enantiomer of the catalyst.
abstract: Alkynyl aziridines can be obtained from the catalytic asymmetric aziridination (AZ reaction) of alkynyl imines with diazo compounds in high yields and high asymmetric inductions mediated by a chiral boroxinate or BOROX catalyst. In contrast to the AZ reaction with aryl- and alkyl-substituted imines, alkynyl imines react to give cis-substituted aziridines with both diazo esters and diazo acetamides. Remarkably, however, the two diazo compounds give different enantiomers of the cis-aziridine from the same enantiomer of the catalyst. Theoretical considerations of the possible transition states for the enantiogenic step reveal that the switch in enantiomers results from a switch from Si-face to Re-face addition to the imine, which in turn is related to a switch from reaction with an E-imine in the former and a Z-isomer of the imine in the latter.
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824 (USA), Fax: (001) 517-3353-1793 http://www2.chemistry.msu.edu/faculty/wulff/myweb26/index.htm.
authors.forename: Yong
authors.initials: Y
authors.lastname: Guan
authors.forename: Maria P
authors.initials: MP
authors.lastname: López-Alberca
authors.forename: Zhenjie
authors.initials: Z
authors.lastname: Lu
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Aman A
authors.initials: AA
authors.lastname: Desai
authors.forename: Aniruddha P
authors.initials: AP
authors.lastname: Patwardhan
authors.forename: Yijing
authors.initials: Y
authors.lastname: Dai
authors.forename: Mathew J
authors.initials: MJ
authors.lastname: Vetticatt
authors.forename: William D
authors.initials: WD
authors.lastname: Wulff
mesh_terms: D000480:Alkynes / Q000138:chemical synthesis* / Q000737:chemistry; D001388:Aziridines / Q000138:chemical synthesis* / Q000737:chemistry; D001391:Azo Compounds / Q000737:chemistry; D002384:Catalysis; D007097:Imines / Q000737:chemistry; D008958:Models, Molecular; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D001388:Aziridines; D001391:Azo Compounds; D007097:Imines; C033132:aziridine
keywords: Asymmetric catalysis; BOROX catalyst; VANOL; VAPOL; aziridine; imine isomerization