Synthesis of Spirocyclic Amines by Using Dipolar Cycloadditions of Nitrones.
Rungroj SaruengkhanphasitDarren CollierIain ColdhamPublished in: The Journal of organic chemistry (2017)
Aliphatic ketones containing a chloride and alkene were heated with hydroxylamine to promote cascade, tandem condensation to oximes, cyclization to nitrones, and 1,3-dipolar cycloaddition to tricyclic isoxazolidines as single stereoisomers. Single regioisomers were obtained when three atoms linked the ketone and dipolarophile to give five-membered rings but mixtures resulted with four atoms in the tether unless a terminal ester was located on the alkene. The N-O bond in the products could be reduced to give spirocyclic amines and diamines.
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