I isolated an Fmoc protected unnatural amino acid. TLC indicating a single product, however NMR in CDCl3 indicating two products. Is there a chance of rotamers?
Protecting the amino function with the Fmoc group converts the former into an carboxamide. Such compounds are known to form "rotamers", the most prominent example for this phenomenon is dimethyl formamide, which is discussed in every textbook about dynamic NMR.