Action of red light on solid (–)-2-chloro-2-nitrosocamphane: nuclear and electron paramagnetic resonance studies, reaction products, and solid-state photolysis reaction mechanisms

Abstract

Analysis of the ¹H n.m.r. spectrum of (–)-2-chloro-2-nitrosocamphane (3) defines its molecular structure. Irradiation of the blue solid rapidly inverts the configuration at C(2) and causes a photochemically initiated Beckmann rearrangement to the nitroxide radical (7). Extended irradiation generates two additional nitroxide radicals (8) and (9), camphor oxime (10), camphor (11), 2-chloro-2-nitrocamphane (12), and 2-chloro-2-nitratocamphane (13). N.m.r. methods show that in (12) the configuration at C(2) is inverted relative to that in the parent chloro-nitroso compound (3). The combination of chemical and spectroscopic evidence enables some of the steps in the solid-state red photolysis reactions of (3) to be unravelled.