Asymmetric synthesis of β-DDB through oxazoline-mediated Ullmann coupling

Article abstract of DOI:10.1080/00397910500186326

Biphenyl lignan (β-DDB) (2), an effective drug in the treatment of hepatitis, was for the first time asymmetrically synthesized via a chiral oxazoline mediated Ullmann coupling. The two enantiomers of β-DDB have been obtained in this way by using the optically pure amino alcohols L-valinol and D-valinol, respectively. However, attempts to synthesize enantiopure α-DDB (1) by the same method failed because of the racemization of 1 at room temperature in solution. Copyright Taylor & Francis, Inc.