Efficient construction of bioactive trans-5A5B6C spirolactones via bicyclo[4.3.0] α-hydroxy ketones.

An efficient, convenient short synthetic procedure for the synthesis of the intricate 5A5B6C-ring fusion topologies of tricyclic spiranoid ß-hydroxybutyrolactones through lactonization of the key intermediate trans-α-hydroxyindenones with malonates is described. All the compounds synthesized exhibited environmentally benign characteristics, moderate fungicidal, nematocidal, and anti-TMV activities.