Stereocontrolled synthesis of syn- and anti-diol epoxide metabolites of triphenylene
The synthesis of both syn- and anti-diol epoxide metabolites of triphenylene has been achieved under complete stereochemical control commencing with commercially available 9-phenanthrol in 18% (9 steps) and 37% (8 steps) overall yields, respectively. The exceptionally high stereoselectivity of the dimethyldioxirane oxidation of trans-dihydrodiol having the quasi-diaxially disposed hydroxyl groups is particularly noteworthy.
Koreeda, Masato,Gopalaswamy, Ramesh,Yang, Jinhai,Tuinman, Roeland J.
Thermodynamically Stable o-Quinodimethane: Synthesis, Structure, and Reactivity
Thermal isomerization of cyclobutaphenanthrene to o-quinodimethane was investigated. Sterically congested substituents or electron-donating substituents on the four-membered ring promoted the ring-opening, affording o-quinodimethane in a relatively stable form. Isolation of the newly prepared o-quinodimethane allowed its structural elucidation and investigation of its potential reactivities. Dual [4+2] cycloaddition of an aryne and o-quinodimethane afforded tetrabenzopentacene, demonstrating the synthetic application of the isolated compound.