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The convenient synthesis of substituted benzopicenes and azabenzopicenes has been achieved by the cationic rhodium(I)/H8-BINAP or BINAP complex-catalyzed [2+2+2] cycloaddition under mild conditions. This method was applied to the synthesis of benzopicene-based long ladder and helical molecules. The X-ray crystal structure analysis revealed that the benzopicene-based helical molecule is highly distorted and the average distance of overlapped rings is markedly shorter than that in the triphenylene-based helical molecule. Photophysical and chiroptical properties of these benzopicene and azabenzopicene derivatives have also been examined. With respect to photophysical properties, substituted benzopicenes and azabenzopicenes showed red shifts of absorption and emission maxima compared with the corresponding triphenylenes and azatriphenylenes. With respect to chiroptical properties, the CPL spectra of the benzopicene-based helical molecule showed two opposite peaks, and thus the value of the CPL was smaller than that of the triphenylene-based helical molecule presumably due to the presence of two chiral fluorophores. [ABSTRACT FROM AUTHOR]

A synthetic procedure for alpha'-aminomethylated enol silyl ethers is described. First, a complex consisting of N-(trimethylsilyl)formaldimine and aluminum chloride is generated through aluminum chloride treatment of (trimethylsilyl)methyl azide. The complex is then allowed to react with different enol triisopropylsilyl ethers to generate the alpha'-substituted enol silyl ethers.

The convenient synthesis of substituted triphenylenes and azatriphenylenes has been achieved by the cationic rhodium(I)/H8-BINAP or BINAP complex-catalyzed [2 + 2 + 2] cycloaddition under mild conditions. Photophysical properties of representative triphenylenes and azatriphenylenes were examined, which revealed that azatriphenylenes showed higher fluorescence quantum yields than triphenylenes. This method was successfully applied to the synthesis of highly fluorescent triphenylene-based long ladder molecules.