Synthetic Access to Cyclopenta[a]inden-2(1H)-ones from Morita–Baylis–Hillman Products of 2-Alkynyl Benzaldehydes

[Image: see text] A new strategy for the synthesis of cyclopenta[a]inden-2(1H)-ones has been developed. An intramolecular Pauson–Khand reaction of the Morita–Baylis–Hillman (MBH) adducts, derived from 2-alkynyl benzaldehydes, provided the consequent novel cyclopenta[a]inden-2(1H)-ones bearing multifunctionalities including an ester group at the fused ring junction (tert-carbon center). The generality of this approach was illustrated by studying the several MBH derivatives containing diverse substitutions/functionalities.