Journal
TETRAHEDRON
Volume 59, Issue 34, Pages 6481-6488Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/S0040-4020(03)01056-1
Keywords
heterohelicenes; McMurry reaction; oxidative photocyclisation; large-scale preparation; NLO properties
Categories
Ask authors/readers for more resources
This paper describes a convenient preparation of tetrathia-[7]-helicene (TH[7]), the generation of the alpha-anion on the terminal thiophene ring, and the synthesis of the 2-formyl-tetrathia-[7]-helicene (2-CHO-TH[7]). The key intermediate trans-1,2-dibenzodithiopheneethene, prepared in 97% yield by McMurry coupling of the 2-formyl-benzo[1,2-b;4,3-b']dithiophene, was transformed into TH[7] using a known procedure. The described method affords TH[7] in 46% overall yield, which is more than four times the yield previously reported in the literature. The alpha-anion of TH[7], which is easily generated on the alpha-position of one of the terminal thiophene rings, reacts with electrophilic reagents such as D2O and DMF. The latter reaction proved to be the best way to prepare 2-CHO-TH[7], a key intermediate for the preparation of new substituted heterohelicenes. (C) 2003 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available