Cesium carbonate → (4-Chloro-3-fluoro-phenyl)-propynoic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

Under argon atmosphere, a four neck flask was charged with 1-chloro-2-fluoro-4-iodo-benzene (50.5 g, 0.20 mol), bis(triphenylphosphine) palladium(II) chloride (2.76 g, 3.94 mmol, 2 mol %), copper(I) iodide (1.50 g, 7.80 mol, 4 mol %) and dry THF (600 ml). At r.t., cesium carbonate (128.3 g, 0.39 mol, 2 eq.) was added over 5 min. Finally, propynoic acid ethyl ester (38.6 g, 0.39 mol, 2 eq.) was added, and the reaction was stirred for 48 h at 35° C. The reaction mixture was evaporated to dryness, and the residue was taken up in toluene (50 ml) and heptane (100 ml). The resulting suspension was stirred at 40° C. for 1 h and filtered afterward over celite. The filtrate was concentrated, and the product was purified by silica gel filtration (toluene/heptane 1:2) to yield 38.8 g (87%) of the Vd as a light yellow solid.

Provenance & Evidence