A diastereoselective and versatile synthesis of the model insect antifeedant 16 related to azadiradione has been achieved in nine steps starting from α-cyclocitral 1. The key steps involve intramolecular alkene addition of an acylradical and a Stille coupling reaction of a vinyl iodide with a stannylfuran.
An efficient synthesis of a model insect antifeedant based on the C, D and E rings of the limonoid azadiradione has been developed. (8 steps ≥ 18% overall yield). The key steps were an electrocyclization induced by acids 4 5 and a dyotropic rearrangement from epoxide 7 to ketone 8.