Table 4. Preparation of Adducts 29a–29g by the [4 + 2] Cycloaddition Reaction^a.

^aReaction conditions: Furan (28) (0.25 mmol), 2-(trimethylsilyl)aryl 4-chlorobenzenesulfonate (7a–7e) (0.375 mmol), CsF (0.75 mmol), and 18-crown-6 ether (0.25 mmol) in PhCN (4 mL) were maintained under stirring at 80 °C for 24 h.

^bIsolated yield.