Rearrangement of aziridine I by MgBr2 gave 2-H-dihydro-17-dehydrovinca
difformine 6. Photolysis transformed aziridines 1 and 11 into the new
compounds 1,2-seco-1,21-cyclovincadifformine 10 and 1,2-seco-1,21-cycl
otabersonine 12. (C) 1998 Elsevier Science Ltd. All rights reserved.