BOC-D-LEUCINOL

Solid

General procedure: To a 10 mL one-neck round-bottomed flask with a magnetic stir bar was added dibenzyl-1-alkylhydrazine-1, 2-dicarboxylates (1a-i) (5 mmol) and Boc2O (5 mmol) in deionized water/MeOH (1:1) (30 mL). To this was added PMHS (20 mmol) followed by catalyst PdCl2 (5 mol percent). The resulting mixture was stirred for 10 h at 25 °C. After completion of the reaction, it was quenched by the addition of aqueous NaOH solution (10 mL) dropwise at 0 °C and then stirred it for additional 3 h. The mixture was then extracted with EtOAc. The organic layer was further washedwith brine (2 x 10 mL) and dried over anhyd. Na2SO4. The solvent was concentrated under reduced pressure to give the crude product, which was purified by column chromatography (petroleum ether/EtOAc) (4:1) as eluent to afford the pure carbamate compounds (2a-i).General procedure: To a 10 mL one-neck round-bottomed flask with a magnetic stir bar was added dibenzyl-1-alkylhydrazine-1, 2-dicarboxylates (1a-i) (5 mmol) and Boc2O (5 mmol) in deionized water/MeOH (1:1) (30 mL). To this was added PMHS (20 mmol) followed by catalyst PdCl2 (5 mol %). The resulting mixture was stirred for 10 h at 25 C. After completion of the reaction, it was quenched by the addition of aqueous NaOH solution (10 mL) dropwise at 0 C and then stirred it for additional 3 h. The mixture was then extracted with EtOAc. The organic layer was further washedwith brine (2 x 10 mL) and dried over anhyd. Na2SO4. The solvent was concentrated under reduced pressure to give the crude product, which was purified by column chromatography (petroleum ether/EtOAc) (4:1) as eluent to afford the pure carbamate compounds (2a-i).