Methanol → (2S,3R)-1-tert-butyl 2-methyl 3-ethylaziridine-1,2-dicarboxylate

Temperature

0 °C

The following step was run duplicate. To a 250 mL round-bottom flask equipped with a stir bar was added (2R,3S)-tert-butyl 2-ethyl-3-formylaziridine-1-carboxylate (one-half of the material isolated in step 1, assumed 20 mmol) as a solution in MeOH (100 ml). The solution was cooled to 0° C. To the solution was added sodium cyanide (1.96 g, 40.0 mmol). The solution was stirred for 10 minutes. To the solution was added oxidation-grade MnO2 (34.8 g, 400 mmol). The mixture was stirred for 10 minutes, then the ice bath was removed and the solution was allowed to warm to room temperature with stirring for 18 hours. The reaction mixture was filtered through a pad Celite and the filter cake was extracted with EtOAc (100 mL). The filtrate was concentrated in vacuo and the resulting orange solid residue was dissolved in water (100 mL) and EtOAc (100 mL) and transfered to a 1 L separatory funnel where the mixture was further diluted with saturated aq. NaCl (“brine”, 100 mL) and EtOAc (100 mL). The mixture was shaken and the phases were separated. The aq. phase was extracted with EtOAc (100 mL). The combined organics were washed with brine (100 mL); dried over MgSO4; filtered; then concentrated in vacuo. The resulting residue was combined with the duplicate run and the combined material was subjected to silica gel chromatography (hexanes:EtOAc, 50:50 to 0:100) to afford (2S,3R)-1-tert-butyl 2-methyl 3-ethylaziridine-1,2-dicarboxylate as a yellow liquid (3.055 g, 33% over two steps).

1. customTo a 250 mL round-bottom flask equipped with a stir bar
2. stirringThe mixture was stirred for 10 minutes
3. customthe ice bath was removed
4. temperatureto warm to room temperature
5. stirringwith stirring for 18 hours
6. filtrationThe reaction mixture was filtered through a pad Celite
7. extractionthe filter cake was extracted with EtOAc (100 mL)
8. concentrationThe filtrate was concentrated in vacuo
9. dissolutionthe resulting orange solid residue was dissolved in water (100 mL)
10. customEtOAc (100 mL) and transfered to a 1 L separatory funnel
11. additionwhere the mixture was further diluted with saturated aq. NaCl (“brine”, 100 mL) and EtOAc (100 mL)
12. stirringThe mixture was shaken
13. customthe phases were separated
14. extractionThe aq. phase was extracted with EtOAc (100 mL)
15. washThe combined organics were washed with brine (100 mL)
16. dry with materialdried over MgSO4
17. filtrationfiltered
18. concentrationthen concentrated in vacuo

ORD record

ord-c0a5c034e97f45c48f41cce87823af33

Source dataset

uspto-grants-2016_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09334279B2