Synthetic Studies on Lycoricidine and Related Compounds. I. Synthesis of 4aH-r, 2H-cis, 2-Hydroxy-8, 9-methylenedioxy-2, 3, 4, 4a-tetrahydro-6 (5H)-phenanthridone

Abstract

4aH-r, 2H-cis, 2-Hydroxy-2, 3, 4, 4a-tetrahydro-8, 9-methylenedioxy-6 (5H)-phenanthridone, which was an important compound lacking two hydroxyl groups at 3-and 4-position in the structure of lycoricidine, was synthesized and configuration of the hydroxyl group was comfirmed to be α-quassi-axial on the basis of NMR data. A new lactam cyclization technique using borontrifluoride etherate on the course from phenethyl isocyanates to the corresponding lactams was examined.