2-(1-Boc-piperidin-4-ylidene)ethanol

tert-Butyl 4-(2-Hydroxyethylidene)piperidine-1-carboxylate

4-(2-Hydroxyethylidene)piperidine-1-carboxylic acid tert-butyl ester

tert-Butyl 4-(2-hydroxyethylidene)tetrahydropyridine-1(2H)-carboxylate