Baylis–Hillman acetates in carbocyclic synthesis: a convenient protocol for synthesis of densely substituted indenes

A simple and facile strategy for synthesis of densely substituted indenes have been developed from Baylis–Hillman acetates in a two step protocol, that is, (1) via treatment with DABCO and then reaction with alkyl 3-oxobutanoates in the presence of K2CO3 (2) followed by the intramolecular Friedel–Crafts cyclization of the resulting keto-diesters using titanium tetrachloride.