35095-07-9

88284-48-4

292638-85-8

35095-07-9

GENERAL METHOD: A mixture of 2-(trimethylmethylsilyl)phenyl trifluoromethanesulfonate (3 mmol, 2.0 eq.), compound (CAS:292638-85-8, 1.0 eq.) and anhydrous cesium fluoride (6.0 eq.) was dissolved in dry acetonitrile (15 mL). The reaction mixture was stirred at room temperature for 12 hours. Upon completion of the reaction, 20 mL of water was added to the mixture and extracted with dichloromethane (3 x 20 mL). The organic phases were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: petroleum ether) to afford the target product methyl benzocyclobutene-1-carboxylate (3c-6c). Compound 5c: pale yellow oil.1H NMR (400 MHz, CDCl3): δ 7.26-7.24 (m, 2H), 7.18 (d, 1H, J = 4 Hz), 7.11 (d, 1H, J = 4 Hz), 4.32 (t, 1H, J = 4 Hz), 3.73 (d, 3H, J = 8 Hz), 3.48 (d, 2H, J = 4 Hz). These data are in good agreement with literature values [14].