Two new types of optically active BODIPY fluorophores bearing chiral phenyl substituents either at the meso-position or at both external alpha-positions have been synthesized. Their chiroptical properties are strongly dependent both on the position of the chiral group and on the protonation of the chromophore. The solid-state structures of one of the difluoroboryl chelates bearing the chiral phenyl substituent at the meso-position (9a) as well as of the corresponding ligand (8a) and its perchlorate have been determined by X-ray diffraction analysis. These are, to the best of our knowledge, the first crystal structures of a dipyrrin free base and of a dipyrrin salt which have been obtained by X-ray diffraction analysis. Hence, for the first time, the helical structure of a protonated dipyrrin chromophore has been proved experimentally.
A short stereospecific synthesis of the carbocyclic 2'-deoxynucleoside analogues 36 and 37 (Schemes 2 and 5) and 45 and 46 (Schemes 2 and 6) starting from optically active 8,9,10-trinorborn-5-en-2-one (1) is described. As two functional groups capable to react with each other are present in the same molecule of the synthetic carbanucleosides, the latter can form polymers similar to oligonucleotides.
A short stereospecific synthesis of the carbocyclic 2'-deoxynucleoside analogues 36 and 37 (Schemes 2 and 5) and 45 and 46 (Schemes 2 and 6) starting from optically active 8,9,10-trinorborn-5-en-2-one (1) is described. As two functional groups capable to react with each other are present in the same molecule of the synthetic carbanucleosides, the latter can form polymers similar to oligonucleotides.
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