Cesium carbonate → HCID 89183375, compound

Participants

Reaction Steps

To a stirred solution of Step 5 intermediate (24.5 g, 70.60 mmol) in dry THF (350 ml) was added cesium carbonate (46.0 g, 141.20 mmol) and allyl boronic acid pinacol ester (23.8 ml, 127.08 mmol) under nitrogen atmosphere and the mixture was degassed for 10 min. Tetrakis(triphenylphosphine)palladium(0) (8.1 g, 7.06 mmol) was added and the reaction was refluxed for 24 h under nitrogen atmosphere. The reaction mixture was diluted with water (250 ml) and extracted with ethyl acetate (3×100 ml). The combined extracts were concentrated and the residue obtained was purified by silica gel column chromatography using 5% ethyl acetate in pet ether to give 4.62 g of the product as an off-white solid; 1H NMR (300 MHz, CDCl3) δ 1.39 (t, J=7.2 Hz, 3H), 3.41 (s, 3H), 3.56 (s, 3H), 4.18-4.24 (m, 2H), 4.31-4.40 (m, 2H), 4.99-5.15 (m, 2H), 5.95-6.03 (m, 1H).

Provenance & Evidence