Like any new process, it takes some practice to extract, understand and convert the information presented from a set of experimental NMR datasets into a fragment.
The only fragment that can accommodate the set of restrictions from a 1H-13C HSQC and HMBC is 2,3-dimethylbutane-1,1-diyl. The green arrows illustrate the 2-3JCH coupling responses extracted from an HMBC experiment.
There is something I do not understand. Why are there 2 CHs coupled and 2 other CHs uncoupled?
ReplyDeleteHello Adolfo,
ReplyDeleteThank you for asking good questions. I really appreciate our discussions on the elucidation process.
If I understand you correctly, the puzzle does not report all the 1H-13C correlations, for example the CH-CH fragment. This was done intentionally in an attempt to mimic a realistic interpretation of an experimental HMBC. It is quite common to have HMBC data with missing or poorly resolved correlations.
Regards,
Arvin