Synthesis of CDE molecular fragments related to sendanin mediated by titanocene(III).

A practical, brief, and diastereoselective synthesis of limonoid CDE fragments from a readily available starting material is described. The key step was the titanocene(III)-promoted cyclization of unsaturated epoxylactones, readily prepared from α-cyclocitral. In this way, we confirm the viability of our procedure for the synthesis of a limonoid model with different functionalization patterns. We also report the antifeedant activity of epoxylactones 18 and 19, which show significant antifeedant activity against Spodoptera littoralis and Spodoptera frugiperda, two insect species with different feeding ecologies.