A COCON analysis of proton-poor heterocycles - Application of carbon chemical shift predictions for the evaluation of structural proposals

The application of the new computer program COCON (Constitutions from Conne ctivities) to the 2D-NMR data sets of three different complex natural produ cts is described. The investigated compounds are proton-poor and therefore underdetermined systems. For such molecules the number of possible constitu tions and the computational speed of COCON are of interest. Our investigati on is focused on how methods of C-13-NMR chemical shift prediction can assi st chemists with regard to refining the selection among the constitutions p roposed by COCON.