1: 34 percent / NEt3 / diethyl ether / 12 h / 40 °C 2: 16 percent Spectr. / p-chloranil / CDCl3 / 240 h / 20 °C View Scheme

diethyl-1,4-dihydro-2,6-dimethyl-3,5-pyridine dicarboxylate; (Bn2NH2)(OCOCF3) in tetrahydrofuran T=20°C; 15 h;

1: 50 percent / diethyl ether / 2 h / Heating 2: 81 percent / pyridine, 4-(dimethylamino)pyridine / tetrahydrofuran / 8 h / Ambient temperature View Scheme

1.1: iPrNEt; Et2BOTf / CH2Cl2 / -78 °C / 1 Torr 1.2: tetrahydrofuran / 23 h / -40 °C 1.3: 70 percent / 1H-imidazole / CH2Cl2 / 11 h / 20 °C 2.1: BuLi / tetrahydrofuran; hexane / 0.5 h / -78 °C 2.2: 91 percent / tetrahydrofuran / 10 h / -40 °C 3.1: 99 percent / DIBAL / toluene / 0.75 h / -78 °C 4.1: SnCl4 / heptane; CH2Cl2 / 0.75 h / -78 °C 4.2: 62 percent / heptane; CH2Cl2 / 1.5 h / -78 °C 5.1: 69 percent / dioxane / 30 h / Heating 6.1: DDQ / CH2Cl2; methanol / 2 h / 20 °C 6.2: 89 percent / PPTS / CH2Cl2; methanol / 6 h / 45 °C View Scheme

1.1: t-butyllithium / tetrahydrofuran; pentane / -78 - 0 °C 1.2: 91 percent / tetrahydrofuran; pentane / -78 - 0 °C 2.1: 55 percent / Dess-Martin periodinane; pyridine / CH2Cl2 / 23 °C View Scheme

sodium tetrahydroborate; cerium(III) chloride

magnesium in tetrahydrofuran T=20°C; 1.5 h;

in diethyl ether 1.) RT, 4 h, 2.) reflux, 2 h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

in tetrahydrofuran; diethyl ether T=0°C; 1 h; Inert atmosphere;

1: With chloro-trimethyl-silane; copper(I) thiophene-2-carboxylate; (R)-p-tol-BINAP in diethyl ether T=-78°C; Inert atmosphere; 2: With hydrogenchloride in methanol; diethyl ether; water Inert atmosphere; optical yield given as percent eeenantioselective reaction;