Bithiophene with winding vine-shaped molecular asymmetry; Preparation, structural characterization, and enantioselective synthesis

Toyomori, Yuka*; Tsuji, Satoru*; Mitsuda, Shinobu*; Okayama, Yoichi*; Ashida, Shiomi*; Mori, Atsunori*; Kobayashi, Toru ; Miyazaki, Yuji; Yaita, Tsuyoshi; Arae, Sachie*; Takahashi, Tamotsu*; Ogasawara, Masamichi*

Preparation of 2,2'-bithiophene derivatives bearing -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 with 5mol% 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. Enantioselective RCM was also achieved by the use of chiral Schrock Hoveyda molybdenum-alkylidene catalyst in up to 87% ee.