The analytical data are consistently agreed with those ones are reported in the literature. Ethyl 2-(piperidin-2-yl)acetate (8). To a solution of KOH (11.2 g, 0.2 mol, 1.0 eq.) in ethanol (80 mL) was added N-Cl piperidine(ethanol) (0.2 mmol) mixture at 0 o C. The mixture was stirring overnight (12-16 hours). After the reaction was completed, the solid was removed by filtration. Washed the solid with ethanol (50 mL) and collected the organic phase. Another ethanol (30 mL) was added to dissolve monoethyl malonic acid (27.3 mL, 0.25 mol, 1.25 eq.) as well as Et3N (41.7 mL, 0.3 mol, 1.5 eq.). Mixed up all the materials and the mixture was heated at 35 o C for 18 hours. After the reaction was completed, the solvent was evaporated under reduced pressure at 43 o C. The residue was dissolved in 30% (w/v) K2CO3(aq) solution (35 mL), and extracted with EtOAc (50 mL× 3). The combined organic phase was washed with sat. NaHCO3(aq.) (25 mL × 2), dried over anhydrous Na2SO4, filtered and evaporated under reduced pressure to give the piperidine monoester (14.7 g, 43%) without further purification. The analytical data are consistently agreed with those ones are reported in the literature. Ethyl 2-(piperidin-2-yl)acetate by the formation of (R)-2-(2-ethoxy-2-oxoethyl)piperidin-1-ium (R)-2-hydroxy-2-phenylacetate (9). To a solution of piperidine monoester (13.7 g, 80 mmol) in methanol (30 mL) was added D-mandelic acid (11.7 g, 88 mmol, 1.1 eq.). After the solid was dissolved, ethyl ether (75 mL) was slowly added to the solution until the fine white precipitate was formed. The mixture was transported to 0 o C refrigerator for 12 hours. The solid was isolated by suction filtration and washed with ethyl ether (75 mL). Collected both solid and solution. The product of (R,R)-mandelate was given as a white foam-like solid (10.8 g, 42%, > 99% ee). (11). To a solution of monoester mandelate 9 (3.23 g, 10 mmol) in ethanol (35 mL) was added Et3N (4.8 mL, 35 mmol, 3.5 eq.), ethyl 3bromopropionate (1.9 mL, 15 mmol, 1.5 eq.) and KOH (560 mg, 10 mmol, 1.0 eq.). The reaction mixture was heated to reflux for 12 hours. After the reaction was completed, the solvent was evaporated under reduced pressure. The residue was dissolved in EtOAc (60 mL), and washed with 30% (w/v) K2CO3(aq) solution (20 mL). The water phase was further extracted with EtOAc (40 mL × 2). The combined organic phase was dried over anhydrous Na2SO4, filtered, and evaporated under reduced pressure to give piperidine diester as a pale-yellow oil (2.43 g, 90% yield) without further purification. The analytical data are consistently agreed with those ones are reported in the literature. (R)-Octahydro-2H-quinolizin-2-one ( ). 1) To a solution of t BuOK (561 mg, 5 mmol, 2.5 eq.) in THF (8 mL) at 0 o C was added piperidine diester (542 mg, 2 mmol). The reaction was stirring at room temperature for 2 hours and then heated to 68 o C to reflux for another hour. After the reaction was completed, the reaction mixture was allowed to cool down to room temperature, then conc. HCl (0.5 mL) was added followed by water (8 mL). The solution was extracted with ethyl ether (3.4 mL × 3). K2CO3 particle was added to the aqueous phase and the aqueous phase was further extracted with ethyl ether (3.4 mL × 3). The combined organic phase was dried over anhydrous Na2SO4, filtered, and evaporated under reduced pressure.