title: Asymmetric N1 unit transfer to olefins with a chiral nitridomanganese complex: novel stereoselective pathways to aziridines or oxazolines.
abstract: Chiral nitridomanganese complex 1 was found to be a highly potential N1 unit source for the asymmetric synthesis of aziridines and 2-oxazolines from olefins such as styrene and its derivatives. When sulfonyl chlorides were employed as activators of the complex in the presence of pyridine, pyridine N-oxide, and a silver salt, the reaction of olefins with complex 1 proceeded smoothly to afford the N-sulfonylated aziridines. The aziridination of styrene derivatives with complex 1 using 2-trimethylsilylethanesulfonyl chloride (SESCl) gave the N-SES-aziridines, which were easily converted into chiral N-unsubstituted aziridines. It was found that the reaction was applicable to the asymmetric synthesis of 2-oxazolines from olefins when acyl chlorides were employed as activators. Complex 1 provided an effective asymmetric environment for trans-disubstituted styrenes in the reaction (up to 92% ee). This is the first example of a direct asymmetric synthesis of 2-oxazolines from olefins. Additional experiments, conducted during the course of this investigation, suggest that the isomerization of the N-acylaziridine intermediate is involved in this reaction.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Nishimura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Minakata
authors.forename: Toru
authors.initials: T
authors.lastname: Takahashi
authors.forename: Yoji
authors.initials: Y
authors.lastname: Oderaotoshi
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Komatsu