Principal component analysis of the 13 C NMR shifts of norbornyl derivatives. II: Tetracyclic dodecane derivatives

Principal component analysis is applied to the 13 C NMR chemical shifts of 29 tetracyclic dodecane derivatives, the spectra of most of which have been recently assigned. These derivatives are subdivided into three classes: exo ‐ endo , exo – exo and endo – endo . Only the seven 13 C shifts of one of the two norbornyl moieties of these derivatives are used in the construction of the data matrix, the other moiety being considered as a ring substituent. This data treatment allows these 29 systems to become a test system for a previously worked (through principal component analysis) standard or training set of 13 C shifts of 55 substituted norbornanes. Only one two‐dimensional principal component projection is necessary for identifying the main structural effects in the chosen norbornyl moiety of the test system, highlighting trends in the 13 C data of these test derivatives and confirming their recent 13 C spectral assignments.