title: Stereocontrolled aziridination of imines via a sulfonium ylide route and a mechanistic study.
abstract: The reaction of N-diphenylphosphinoyl imines 1 with [3-(trimethylsilyl)allyl]dimethylsulfonium bromide (5) in the presence of NaH at room temperature predominantly gave trans-vinylaziridines 4. On the other hand, cis-vinylaziridines 4 were the main products when the preformed ylide prepared from the reaction of [3-(trimethylsilyl)allyl]diphenylsulfonium perchlorate (6) was reacted with the same imines 1 at low temperature. trans-Aziridines were also obtained when imines 1 and sulfinimines 9 were reacted with N,N-dimethylacetamide-2-dimethylsulfonium bromide (7) in the presence of a base, respectively. A mechanistic study showed that the stereochemistry of these reactions was controlled by the reactivity of the imines and ylides. A higher reactivity of imines and ylides favors the formation of cis-aziridines, whereas a lower reactivity leads to trans-products.
authors.affiliation: State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fengling Road, Shanghai 200032, China.
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Yang
authors.forename: Ming-Jie
authors.initials: MJ
authors.lastname: Zhang
authors.forename: Xue-Long
authors.initials: XL
authors.lastname: Hou
authors.forename: Li-Xin
authors.initials: LX
authors.lastname: Dai