Cesium carbonate → 4-Chloro-2-(1-oxo-5,6,7,8-tetrahydro-1H-pyrrolo[3,4-b]indolizin-2(3H)-yl)nicotinaldehyde

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 238d (400 mg, 2.27 mmol), 2-bromo-4-chloronicotinaldehyde (1.50 g, 6.90 mmol, 3.0 eq.), Pd2(dba)3 (208 mg, 0.227 mmol, 0.1 eq.), xantphos (131 mg, 0.227 mmol, 0.1 eq.), Cs2CO3 (1.50 g, 4.54 mmol, 2.0 eq.), and dioxane (30 mL). After bubbling nitrogen through the resulting mixture for 30 minutes, the reaction mixture was stirred at 90° C. for 16 h. After the reaction was complete, the mixture was cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure and the residual was purified by silica-gel column chromatography eluting with 1:3 ethyl acetate/petroleum ether to afford 238e (300 mg, 42%) as a light yellow solid. MS-ESI: [M+H]+ 316.1.

Provenance & Evidence