Photochemically induced cyclization of N-[2-(o-styryl)phenylethyl]acetamides and 5-styryl-1-methyl-1,2,3,4-tetrahydroisoquinolines: new total syntheses of 1-methyl-1,2,3,4-tetrahydronaphtho[2,1-f]isoquinolines

Two new total syntheses of 1-methyl-1,2,3,4-dihydronaphtho[1,2-f]isoquinolines are based on the construction of their phenanthrene ring system by photochemically induced cyclization of N-{2-[(E)-2-phenyl-1-ethenyl]phenylethyl}acetamides or 1-methyl-5-[(E)-2-phenyl-1-ethenyl]-1,2,3,4-tetrahydroisoquinolines.