Development of New CD Methods for Determining the Absolute Stereochemistry of Chiral Molecules

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1. In this project, we have developed a new strategy for determining the absolute configuration of mono- functional compounds by the CD exciton chirality method. (1) An achiral CD auxiliary with two naphthalene chromophores was designed. (2) The CD auxiliary was connected with chiral mono-alcohols. (3) The chirality of the alcohol part was transferred to the CD auxiliary. (4) Two naphthalene chromophores took a chiral conformation generating exciton CD. (5) To determine the absolute configuration of the alcohol, the exciton chirality was determined by the semi-empirical MO and/or empirical MM methods. (6) The calculated exciton chirality was compared with the observed exciton CD. The absolute configurations of various chiral mono-alcohols and mono-carboxylic acids have been thus determined by this new strategy of the CD exciton method.2. One of the ultimate research goals of material science would be the construction of molecular machines, where one molecule mechanically works as a mac … More hine by external energy sources. We have recently succeeded in the first construction of a molecular machine, a light-powered chiral molecular motor, which photochemically rotates only in one-direction reflecting the chirality of the motor molecule. The motor rotation is controlled by the irradiation of light and molecular chirality.3. Since we reported facile synthesis of thiacalix[4]arene (TCA), we have studied the unique stereochemistry arising from the bridging sulfur. (1) The conformations of thia-, sulfinyl-, and sulfonylcalix[4]arenes were fixed by coordination of S and/or O atoms to metal ion. (2) All configurational isomers of sulfinylcalix[4]arenes were prepared. (3) Chiral disulfinylcalix[4]-arenes were prepared by oxidation of two adjacent sulfurs of TCA. (4) New molecular chirality was constructed by mono-oxidation of 1,3-altemate-TCA. (5) Chelation-assisted nucleophilic aromatic substitution to sulfinyl- and sulfonylcalix[4]arenes has been studied. (6) Chiral stationary phases for GC were prepared by introducing chiral amides into TCA. Less