Inversion of configuration of alcohols with O-alkyl-N,N'-dicyclohexylisoureas

Article abstract of DOI:10.1055/s-1991-26495

(S)-(+)-N,N'-Dicyclohexyl-O-(1-methylheptyl)isourea [(S)-2] reacts with acetic acid in cyclohexane to give (R)-(-)-(1-methylheptyl) acetate [(R)-3] with 100% inversion of configuration. Reaction of isourea (R)-2 with phenol proceeds also with inversion of configuration (99.8%) yielding (S)-(+)-(1-methylheptyl) phenyl ether [(S)-4] as the main product; optically active 2- and 4-(1-methylheptyl)phenols [(S)-5] and [(S)-6], respectively, are formed simultaneously. These byproducts, besides others resulting from hydride-shifts, document that the mechanism proceeds via the methylheptyl cation intermediate.