Novel photoadditions of tertiary amines to the α-position of α,β-unsaturated γ,δ-epoxy nitriles

Abstract

The photoreactions of α,β-unsaturated γ,δ-epoxy nitriles 1, 2, 13 and 16 with triethylamine give rise to novel 1 ∶ 1 α-adducts (e.g., 5) efficiently. After treatment with silica gel, the adducts undergo retro-Michael reaction leading to the corresponding α-alkylidenenitrile derivatives (e.g., 3). The epoxy nitrile 1 also reacts with various tertiary amines to afford α-adducts. The reaction of 1 and the silylamine 24 gives mainly methylene derivative 22 and silylated compound 25 after treatment with silica gel. The reaction may proceed via single- electron-transfer from the amine to the excited epoxy nitrile.