An oxazoline based approach to (S)-gossypol

Article abstract of DOI:10.1016/S0040-4020(98)00501-8

(S)-Gossypol (S)-1, a yellow pigment of cottonseed, has been accessed by a total asymmetric synthesis. The sequence leading to (S)-gossypol (S)-1 was highlighted by four oxazoline mediated reactions, including coupling of ortho-(methoxy)aryloxazolines with Grignard reagents, butyllithium based ortho-lithiation of aryloxazolines, stereocontrolled Ullman couplings of bromonaphthyloxazolines, and ethoxyvinyllithium hexamethylphosphoric triamide complex based ortho-lithiation of aryloxazolines.