Spirocyclopropane Isoxazolidines, Octahydropyrindin-4-ones and β–Lactams with Biomimetic Ethylene Release from the Electrophilic Substitution of a 1,1-Ethyleneallylzinc Complex

Electrophilic substitution of 1-ethenylcyclopropyl mesylate by 3,3-diethoxypropanal in the presence of palladium(0) (5%) and diethylzinc (2 equivalents) provided 5-cyclopropylidene-1,1- diethoxy-3-hydroxypentane; its nitrone derivatives underwent intramolecular cycloaddition to provide spirocyclopropane isoxazolidines, which then were transformed under thermal or acidic conditions, into octahydropyrindin-4-ones or bicyclic b-lactams with the ethylene phytohormone extrusion, respectively. Use of chiral auxiliaries, i.e, (L)-2-acetoxylactate can lead to enantiomerically enriched heterocycles.