Hexaphenylbenzene-based porous organic polymers are prepared smoothly through palladium-catalyzed CÀC coupling polymerization. According to the obtained nitrogen physisorption isotherms, the Bru-nauerÀEmmettÀTeller specific surface area for these polymers varies between 742 and 1148 m 2 g À1 . Gravimetric hydrogen adsorption isotherms show that the adsorption capacity for hydrogen is up to 1.5 wt % at 1.13 bar and 77 K. Thanks to the propeller-like structure, unique electronic feature, and efficient preparation, hexaphenylbenzene can be taken as a promising building block for designing porous polymers with special properties.
4-Arylhexahydroindole derivatives 5 were synthesized from 2-arylcyclohexenyl allylamine derivatives 4, which have a large protecting group on nitrogen, using zirconium-promoted cyclization. Reaction of 4e with Cp(2)ZrBu(2), followed by treatment with MeMgBr and then O(2), gave 2a in 63% yield by a one-pot reaction, since the approach of O(2) to zirconium was prevented by the aryl group. The total syntheses of (+/-)-mesembrane and (+/-)-mesembrine were achieved starting from 2a. To synthesize these natural products in a chiral form, the starting allylamine derivative 24 (80% yield, 86% ee, recrystallized from MeOH, 99% ee with 79% recovery) was prepared from allyl carbonate 22a and N-tosylallylamine 23 using palladium-catalyzed asymmetric amination in the presence of (S)-BINAPO as a chiral ligand. (-)-Mesembrane and (-)-mesembrine were synthesized from this allylamine 24.
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