LiClO4-catalyzed highly diastereoselective synthesis of cis-aziridine carboxylates

Aliphatic aldehydes in the synthesis of carbo- and heterocycles. Part I. Synthesis of three-, four-, and five-membered rings

“…For example, chiral quaternary ammonium salts as phase-transfer catalysts ensured synthesis of oxiranes in quantitative yield and with high stereoselectivity [18,19]. Enantioselective synthesis of 2-benzothiazolyloxiranes [20], diastereoselective synthesis of 2-oxiranylthiazoles [11], enantio-and diastereoselective synthesis of α,β-epoxy-α′-silyl ketones [21] and cis-vinyl epoxides [22], and syntheses of vinyl epoxides catalyzed by tetrahydrothiophene [23] and methylrhenium trioxide [24] were reported. Fluorinated oxirane was synthesized from bromo-(tert-butyldimethylsilyl)fluoromethyllithium [25].…”

“…Three-component condensation of aliphatic aldehydes 9b and 9d-9f with various amines 15 and ethyl diazoacetate 16 under mild conditions in acetonitrile in the presence of LiClO 4 and iridium complexes [8], La(OTf) 3 , Sc, Y, Nd, Dy, Eu, Gd, Er, or Yb salts [9], or ionic liquid [bmim] [PF 6 ] gave aziridine derivatives 17 with high cis-diastereoselectivity (cis-trans ratio 5 : 1) [10,11] (Scheme 4).…”

Three‐Membered Heterocycles. Structure and Reactivity

“…In this case, the solvent itself is presumed to fulfill the role of Lewis acid [100]. An operationally attractive procedure has been reported in which the aldimine is formed in situ using lithium perchlorate as a catalyst (entry 3), providing exclusively the cis isomer [101].…”

K-10-Catalyzed Highly Diastereoselective Synthesis of Aziridines

“…Our observations agreed with literature data when achiral Lewis acids were used and gave cis-aziridine as a major product. [4][5][6][7]11 Fumaric acid or maleic acid derivatives, which are typical for carbene-involved mechanisms, are not observed in the reaction mixture as byproducts (GC-MS). 12,13 Therefore, we propose that the mechanism of aziridination on K-10 is based on activation of the imine moiety by K-10 making the nucleophilic attack of ethyl diazoacetate possible.…”