Asymmetric Synthesis of 4-Phenyl-1,5-diazacyclooctan-2-one Using Optically Active Vinyl Sulfoxides.

Both enantiomers of (S)- and (R)-4-phenyl-1,5-diazacyclooctan-2-ones (7) were synthesized stereoselectively with good optical purity by the asymmetric conjugate addition of pyrazolidine to optically active vinyl sulfoxides, t-butyl (E)-2-[(R)- and (S)-p-tolylsulfinyl]cinnamates, respectively. Starting from 7, a synthesis of optically active homaline was achieved.