title: Asymmetric synthesis of 2-(2-pyridyl)aziridines from 2-pyridineimines bearing stereogenic N-alkyl substituents and regioselective opening of the aziridine ring.
abstract: The addition of chloromethyllithium to the imine derived from 2-pyridinecarboxaldehyde and (S)-valinol, protected as its O-trimethylsilyl ether, gave the 1,2-disubstituted aziridine with good yield and diastereoselectivity. The analogous reaction performed on the imine derived from (S)-valine methyl ester gave the product containing the aziridine ring and the alpha-chloro ketone group coming from the attack of chloromethyllithium to the ester function. Other stereogenic alkyl substituents at nitrogen gave less satisfactory results. Moreover, the aziridination protocol did not work on other aromatic imines which were not capable of bidentate chelation, e.g., 3- and 4-pyridineimine and benzaldimine. Preliminary studies showed the possibility to carry out regio- and stereospecific opening reactions of 2-(2-pyridyl)aziridines by attack of internally generated or external nucleophiles.
authors.affiliation: Dipartimento di Chimica G. Ciamician, Università di Bologna, via Selmi 2, 40126 Bologna, Italy. diego.savoia@unibo.it
authors.forename: Diego
authors.initials: D
authors.lastname: Savoia
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Alvaro
authors.forename: Romano
authors.initials: R
authors.lastname: Di Fabio
authors.forename: Andrea
authors.initials: A
authors.lastname: Gualandi
authors.forename: Claudio
authors.initials: C
authors.lastname: Fiorelli
mesh_terms: D001388:Aziridines / Q000138:chemical synthesis*; D007097:Imines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism
chemical_list: D001388:Aziridines; D007097:Imines