Studies on the Synthesis of Substituted Phenanthrenoids

Article abstract of DOI:10.1021/jo01294a035

Highly regioselective reactions for the construction of polysubstituted benzenes 18, 19, 20, 22, 24, and 44-47 are described, including some remarkable site-selective halogenations.These have been employed in the synthesis of halo-, nitro-, amino-, and urethane-substituted stilbenes 37, 38, and 51-56.Ideas for thermal as well as photochemical cyclizations are presented and explored.Stilbene 54 led to the formation of phenanthrenes 57, 58, and 62; likewise 55 furnished two new tricyclics, 60 and 61, whereas irradiation of 52 in tert-butylalcohol captured solvent to produce phenanthrenes 63 and 64.Strategies for the total synthesis of juncusol (1), a cytotoxic phytoalexin, are considered.