1: trimethylsilylacetylene With lithium diisopropyl amide in tetrahydrofuran; hexane T=-78°C; 0.5 h; 2: With zinc dibromide in tetrahydrofuran; hexane T=-78 - 0°C; 0.5 h; 3: 4-bromo-6-methyl-2H-pyran-2-one With tetrakis(triphenylphosphine) palladium(0) in tetrahydrofuran; hexane T=0 - 25°C; Negishi reaction;

1: 79 percent / PBr3 / dimethylformamide / 70 °C 2: 82 percent / PPh3; Et3N; CuI / 10 percent Pd/C / acetonitrile / 3 h View Scheme