Synthesis of Optically Active Bis(2‐oxazolines): Crystal Structure of a 1,2‐Bis(2‐oxazolinyl)benzene ZnCl2 Complex

Abstract Dinitriles (5–7, 12, 13) react with enantiomerically pure β‐amino alcohols (8 – 11,17) under zinc chloride catalysis to give optically active C2‐symmetric bis(oxazolines). 1,2‐Bis(2‐oxazolin‐2‐yl)benzenes 1a – e are obtained under mild reaction conditions. 1H‐NMR spectroscopy indicates the formation of 1:1 complexes 23 of these compounds with ZnCl2. The energy required for a conformational interconversion of zinc dichloride complex 23e was determined by variable‐temperature 1H‐NMR studies. An X‐ray structure analysis was performed with the substituted [1,2‐bis(2‐oxazolinyl)benzene]zinc dichloride complex 23a.