1-(tert-Butoxycarbonyl)-1,2,3,6-tetrahydropyridin-4-yl-trifluoromethanesulfonatetert-butyl 4-[(trifluoromethyl)sulfonyloxy]-5,6-dihydropyridine-1(2H)-carboxylatetert-Butyl 4-(((trifluoromethyl)sulfonyl)oxy)-5,6-dihydropyridine-1(2H)-carboxylate4-Trifluoromethanesulfonyloxy-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester