Bithiophene with Winding Vine-shaped Molecular Asymmetry. Preparation, Structural Characterization, and Enantioselective Synthesis

Preparation of 2,2'- bithiophene derivatives bearing omega-alkenyl groups at the 3,3'-positions and ring-closing metathesis reactions of the obtained compound were performed. The reaction of bithiophene bearing 3-butenyl substituents 1 with 5 mol% Grubbs 1st generation catalyst underwent ring-closing metathesis (RCM) to afford the cyclized product 7 showing winding vine-shaped molecular asymmetry in up to 88% yield. Enantio-selective RCM was also achieved by the use of chiral Schrock-Hoveyda molybdenum-alkylidene catalyst in up to 87% ee.