Hetero-and Homonuclear 2D-Resolved Spectra

The only assignments that remain are those of carbon signals 9 and 10. 

There is also a heteronuclear version of the 7-resolved experiment, known as HET2DJ. The most common examples involve the spectrum displayed as decoupled singlets 

So far we have discussed homonuclear 2D H,H-shift correlation spectroscopy (H,H-COSY) as well as heteronuclear 2D C,H-shift correlation spectroscopy (C,H-COSY, or C,H-HSC). Let us now consider homonuclear 2D C,C-shift correlation spectroscopy. 

Suppose we could devise a 2D NMR technique to map out all one-bond C-C couplings. What would be the value of such data A moment s reflection should convince you that this information would provide the carbon-carbon connectivity (the carbon backbone) of the entire molecule This is the single most useful piece of information in the elucidation of organic structure. But how can we accomplish it  

Recall how we could use the small satellites present in a H spectrum to determine the magnitude of one-bond C-H coupling constants (Section 8.6.1). Now we will need to use satellites in the proton-decoupled spectrum to map out all one-bond couplings This will not be easy, 

QUATE multiplet corresponding to signal 4 in the spectrum of 2-chlorobutane. Because the two one-bond coupling constants are nearly equal (ca. 35 Hz between tetrahedral carbons Section 9.3), the two doublets are barely resolved, appearing instead as one doublet at lower resolution. 

---