Biphenyl-oxazoline ligands derived from β-DDB: Their synthesis and application in asymmetric pinacol coupling reaction

Biphenyl-bisoxazoline ligands conveniently synthesized from β-DDB have been exploited in asymmetric pinacol coupling reaction for the first time. The pinacol products were obtained with good yields, high diastereoselectivities and good enantioselectivities (up to 83%e.e.). The stereochemistry of the diol products was dominated by the steric structure of the oxazoline component. Ligands bearing bulky groups in the chiral centre of the oxazolines showed more efficient for achieving both high diastereoselectivity and enantioselectivity.