79102-27-5Relevant academic research and scientific papers
Asymmetric N1 unit transfer to olefins with a chiral nitridomanganese complex: Novel stereoselective pathways to aziridines or oxazolines
Nishimura, Masaaki,Minakata, Satoshi,Takahashi, Toru,Oderaotoshi, Yoji,Komatsu, Mitsuo
, p. 2101 - 2110 (2007/10/03)
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 (SESC1) 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 I 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.
HOMOLYTIC AZIRIDINE OPENING (AZA VARIANT OF CYCLOPROPYLCARBINYL-HOMOALLYL REARRANGEMENT) BY ADDITION OF TRIBUTYLTIN RADICAL TO N-ACYLAZIRIDINES. FACTORS CONTRIBUTING TO THE REGIOSELECTIVITY
Werry, Juergen,Stamm, Helmut,Lin, Pen-Yuan,Falkenstein, Reinhard,Gries, Stefan,Irngartinger, Hermann
, p. 5015 - 5028 (2007/10/02)
AIBN initiated reaction of N-acylaziridines 1 with Bu3SnH in refluxing benzene provided products 5 and 8 of reductive ring opening.Yields (practically quantitative in most cases) fell drastically with steric hindrance of the addition of Bu3Sn to the acyl oxygen of 1.They depended to some extent on the experimental conditions for hydrogen capturing when aziridine homolysis provided a primary radical 3 or 6.The regioselectivity of (probably reversible) ring homolysis can be understood in terms of the stability of the arising radical (3, 6), of stereoelectronic control (e.g. 1i as compared to 1h) and of frontier orbital interactions (1j).A possible difference in bond lengths as explanation for the formation of the primary radical from 1j did not find support from an X-ray structure analysis of N-tosyl-2-methyl-aziridine 11.Isomeric products were obtained only twice (1i, 1j) with a dependence of the ratio 5j:8j on concentration and hydrogen isotope of Bu3SnH.No such dependence was found for the ratio 5:14 (reduction without and with an intervening cyclization of 3 leading to a pyrrolidone) obtained from the N-cinnamoylaziridine 1l.This ratio (1:9 for 1l and 1:3 for 1n) must reflect the E-Z isomers in 3.The observed preference for the formation of E-3 from 2 can be explained by stereoelectronic and steric effects.A cinnamoyl double bond in 5 was saturated depending on experimental conditions.
Ring Opening of Aziridines by Different Fluorinating Reagents: Three Synthetic Routes to α,β-Fluoro Amines with Different Stereochemical Pathways
Alvernhe, Gerald M.,Ennakoua, Christine M.,Lacombe, Sylvie M.,Laurent, Andre J.
, p. 4938 - 4948 (2007/10/02)
The syntheses of α,β-fluoro amines from the reaction of secondary aziridines with either Olah's reagent (HF, pyridine) or anhydrous hydrogen fluoride and of N-activated aziridines with partially neutralized Olah's reagent (NR3-nHF) are reported.The stereo
