Brønsted acid-catalysed desilylative heterocyclisation to form substituted furans

Heterocyclisation of -butyldimethylsilyl (TBS) protected γ-hydroxy-α,β-unsaturated ketones catalysed by -toluenesulfonic acid ( -TSA) to form substituted furans is reported. The reaction proceeds under mild conditions at room temperature in methanol to give a range of furan products (21 examples, up to 98% yield). Mechanistic experiments suggest the reaction proceeds deprotection followed by catalytic dehydrative heterocyclisation.