October 29, 2012
With any unknown compound, there always seems to be lots of choices.
For this unknown, it seems quite straightforward to consider the carbon of the CH group as an sp2 with a carbon shift of 113.0 ppm and proton shift of 7.0 ppm.
However, there are cases where the carbon may not be an sp2. Below is a substructure of a bis-furan compound1 where one of the bridging CH groups is an sp3 despite the high 1H and 13C chemical shifts of 7.0 and 113.0 ppm, respectively.
Thank you Walter and TLP for your comments to Puzzle #35.
- J. Nat. Prod. 2002, 65, 1734-7. http://www.ncbi.nlm.nih.gov/pubmed/12444718