ethyl rel(3R,4R,5S)-4-hydroxy-5-methyl-3-(2-oxopropyl)piperidine-1-carboxylate

ethyl 5-methyl-3-(2-oxopropyl)-1,2,3,6-tetrahydropyridine-1-carboxylate

ethyl 3-(1,3-dioxolan-2-ylmethyl)-4-hydroxy-5-methylpiperidine-1-carboxylate

ethyl 10-methyl-6-(2-oxoethyl)-1,4-dioxa-8-azaspiro[4.5]decane-8-carboxylate

ethyl 3-(1,3-dioxolan-2-ylmethyl)-5-methyl-1,2,3,6-tetrahydropyridine-1-carboxylate