Photochemical Synthesis of Spirocyclohexylisoquinolines, Analogues of (±)-Galanthamine and (±)-Lycoramine

Abstract
Photocyclization of N-arylenamides 10, 15 and 16 led efficiently to spirotricyclic δ-lactams 5, 6 and 7. Compound 7 was easily and stereospecifically transformed in two steps into spirocyclohexylisoquinolines 3 and 4 which show structural analogies with some Amaryllidaceae alkaloids, galanthamine 1 and lycoramine 2.