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Determination of the Absolute Configuration of Inherently Chiral Resorc[4]arenes

“…The aminolysis of this resorc [4]arene using (-)-1-phenylethylamine as solvent at 160°C leads to the tetraamides (-)-3a and (+)-3b (Figure 1). In fact, by heating just to 100°C only up to three methyl ester moieties were transformed.…”

“…Since the diastereomers can be separated without HPLC these enantiomerically pure resorc [4]arenes are interesting synthons for further syntheses. In addition, this synthetic route is the best way to obtain enantiomerically pure inherently chiral resorc [4]arens in high yields and in a half gram scale, so far.…”

“…In addition, this synthetic route is the best way to obtain enantiomerically pure inherently chiral resorc [4]arens in high yields and in a half gram scale, so far.…”

“…Synthesis of inherently chiral calix [4]resorcarenes [1] includes the reaction of achiral resorcarenes with camphorsulphonic chloride, [2] hydrophosphorylderivatives, [3] trimethylsilyl isocyanates, [4] 1,3-oxazine formation [5,6] or introduction of the chiral axis during cyclization process. [7][8][9] However, not in all cases the enantiomers were separated and the absolute configuration of the pure enantiomers is often unknown.…”

“…The reaction of 2-bromomethyl acetate with deprotonated resorc [4]arenes was often performed to extend the cavity size or to provide a carboxy group at the upper rim of the macrocycle. [11] At that point the methyl ester can e.g.…”