82483-97-4Relevant articles and documents
Two Practical and Efficient Approaches to Fluorinated and Nonfluorinated Chiral β-Imino Sulfoxides
Fustero, Santos,Navarro, Antonio,Pina, Belen,Asensio, Amparo,Bravo, Pierfrancesco,Crucianelli, Marcello,Volonterio, Alessandro,Zanda, Matteo
, p. 6210 - 6219 (1998)
Reaction of fluorinated and nonfluorinated N-substituted imidoyl chlorides 1 with lithium derivatives of enantiopure methyl p-tolyl sulfoxide 2a (or racemic methyl phenyl sulfoxide 2b) gave a wide variety of chiral N-substituted β-imino sulfoxides 4 in good to excellent yields. The title compounds (R)-4 were also prepared by aza-Wittig reaction of γ-fluoro-β-keto sulfoxides (R)-5 and N-aryl iminophosphoranes 6. The imino - enamino equilibrium was studied, showing, in all instances, the imino form as the predominant tautomer independent of the nature of the N-substituent. The configuration of the C=N double bond was found to be Z for both N-alkyl and N-aryl derivatives on the basis of 1H NMR NOE difference experiments performed over several compounds. Ab initio calculations (HF/6-31G*) carried out on several representative examples of 1 and 4 are, in general, consistent with the experimental results.
