Cesium carbonate → (S)-tert-Butyl 4-(5-(Diphenylmethyleneamino)pyrazin-2-yl)-3-methylpiperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 230a (2.6 g, 7.3 mmol), diphenylmethanimine (1.3 g, 7.3 mmol), Pd2(dba)3 (669 mg, 0.73 mmol), (R)-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (968 mg, 1.46 mmol), Cs2CO3 (4.7 g, 14.6 mmol), and 1,4-dioxane (40 mL). After three cycles of vacuum/argon flush, the mixture was heated at 96° C. for 3 hrs. It was then cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure and the resulting residue was purified by silica-gel column chromatography eluting with petroleum ether/ethyl acetate (10:1 to 3:1) to afford 230b as red oil (3.3 g, 75%). MS: [M+H]+ 458.3.

Provenance & Evidence