OXYGEN TRANSFER DURING THE COPPER INDUCED REACTION OF α,β-EPOXY DIAZOMETHYL KETONES

Article abstract of DOI:10.1016/0040-4020(80)80106-2

Reactions of α,β-epoxy diazomethyl ketones 1a-i with activated copper powder or copper(II) sulfate in methanol (or ethanol) lead to 1,1-dialkoxy-but-3-ene-2-ones 2 (or 3) in good yields.This process of oxygen transfer proceeds via initially generated keto-carbenoids which react intramolecularly with the epoxide function to give bicyclic intermediates 10.Release of strain and subsequent ring opening produces but-2-ene-1,2-diones which acetalise to give the ultimate reaction products 2 (or 3).With copper as catalyst byproducts were isolated viz 1,1-dialkoxy-4-hydroxy-butane-2-ones (4 and 5), and indanone derivate 6.An explanation for these side reactions has been given.