Tetrahydrofuran → HCID 117966661, compound

Participants

Reaction Conditions

Reaction Steps

A solution of (R)-1-tert-butyl 2-ethyl 6-oxopiperidine-1,2-dicarboxylate (D19) (0.5 g, 1.84 mmol) in toluene (5 ml) was cooled at −50° C. LiEt3BH 1M solution in THF (1.93 ml, 1.93 mmol) was added dropwise in a manner that the reaction temperature did not exceed −45° C. After complete addition the mixture was stirred at −45° C. for 30 minutes. DIPEA (1.38 ml, 7.92 mmol) was added to the reaction maintaining the temperature below −45° C. followed by the addition of DMAP (3.4 mg, 0.027 mmol). The reaction mixture was then charged with TFAA (0.3 ml, 2.11 mmol) keeping the temperature below −45° C. After complete addition, the reaction mixture was warmed to 20-25° C. within one hour and kept for an additional 4 hrs at this temperature. Reaction mixture was quenched by slow addition of water. Phases were separated and the organics washed with water, dried over Na2SO4 and concentrated to obtain a clear oil, which was used as such to be subjected to the same procedure once again to afford the title compound (D20) (260 mg).

Provenance & Evidence