DescriptionRevealed are studies on the reactivity and mechanism of spirodiepoxides and their utilization in the synthesis of highly functionalized diverse motifs. New spirodiepoxide based methodologies have been discussed including the method for synthesis of syn substituted hydroxyketone, diendiol, diyndiol, α′-hydroxy-γ-enone, dihydrofuranone, butenolide, and δ-lactone. Two complementary and stereochemically divergent methods for the synthesis of oxetan-3-ones starting from allenes via spirodiepoxides are also presented. Spirodiepoxide based cascades have also been used in the studies towards the synthesis of pectenotoxin 4 (PTX4). An unprecedented hydrogen bond directed allene epoxidation and spontaneous opening of the spirodiepoxide by the free hydroxyl group was employed in the synthesis of the F ring of PTX4. Improved protocol for the synthesis of allene and a new method for the synthesis of bromohydroxyketone have also been disclosed.