In this paper, an efficient synthesis of the two attractive fused thiophenes: helicene (1) and double helicene
(2) bearing chiral chains was developed via multi-step moisture sensitive reactions in ca. 10.5 % and ca. 6.0 % isolated
yields, respectively, with dithieno[2,3-b:3',2'-d]thiophene (7) as a starting material. However, 1 and 2 showed no optical
rotations due to the too weak contribution from chiral induction of the chiral chain, (S)-3,7-dimethyl-octyl group in the
formation of helicenes.
Keywords: helicene, chiral chain, double helicene, thiophene-based, synthesis
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