Silicon Spiro Double Helicene-like Compounds Based on Dithieno[2,3-b:3',2'-d]thiophene: Syntheses and Crystal Structures

J Org Chem. 2015 Nov 6;80(21):11156-61. doi: 10.1021/acs.joc.5b01910. Epub 2015 Oct 22.

Abstract

Silicon spiro carbon-sulfur double helicene-like compounds 1 and rac-2 were synthesized from 2,5-bis-trimethylsilanyldithieno[2,3-b:3',2'-d]thiophene, with total yields of 17% and 7%, respectively. (1)H and (13)C NMR spectra and X-ray crystallographic analysis showed the predicted 4-fold symmetry for 1 and rac-2 and confirmed their spiro double helicene-like spatial configurations. The absorption behavior of compounds 1 and rac-2 was also investigated.