Carbon-13 chemical shifts of substituted nortricyclenes

¹³C NMR spectra of a series of substituted nortricyclene derivatives have been measured, and the ¹³C chemical shifts interpreted in terms of α, β, γ and δ-effects. The nature of these substiuent shifts is discussed together with some analytical possibilities. The substituent shifts provide valuable data about the steric effects in strained molecules and can be used as increments for structural analysis, particularly for the determination of orientations of substituent groups.