TY - DATA T1 - Solvent-Induced Reversed Stereoselectivity in Reciprocal Resolutions of Mandelic Acid and erythro-2-Amino-1,2-diphenylethanol PY - 2013/09/20 AU - Hiroaki Shitara AU - Toshiki Shintani AU - Koichi Kodama AU - Takuji Hirose UR - https://acs.figshare.com/articles/dataset/Solvent_Induced_Reversed_Stereoselectivity_in_Reciprocal_Resolutions_of_Mandelic_Acid_and_i_erythro_i_2_Amino_1_2_diphenylethanol/2374822 DO - 10.1021/jo401517q.s008 L4 - https://ndownloader.figshare.com/files/4014328 KW - thermogravimetric analysis KW - dioxane KW - Reciprocal Resolutions KW - sheetlike structure KW - pseudopolymorphic salt crystals KW - diastereomeric salt KW - IR spectra KW - erythro KW - crystallization KW - stereocontrol technique KW - crystal structures KW - 1 H NMR spectra KW - resolution process KW - equimolar amount N2 - Solvent-induced chirality switching in reciprocal optical resolution between mandelic acid (1) and erythro-2-amino-1,2-diphenylethanol (2) has been demonstrated. The stereochemistry of the deposited salts was controlled by changing the crystallization solvent from 1-PrOH or 1-BuOH to 1,4-dioxane. It was revealed from 1H NMR spectra, thermogravimetric analysis, and X-ray crystallography of the salts that an equimolar amount of the crystallization solvent was incorporated in each diastereomeric salt. On the basis of the crystal structures, it was found that both the hydrogen-bonding ability and the size of the solvent molecule played an important role. Differences in the formed hydrogen-bonding networks (columnar or sheetlike structure) and their packing manner were found to be crucial for the reversed stereoselectivity. Furthermore, pseudopolymorphic salt crystals that incorporated 1,4-dioxane were obtained during the enantioseparation of racemic 2, and their solid-state properties were examined by measurement of their IR spectra. This solvent-induced dual stereocontrol technique was successfully applied to the successive resolution process, eliminating the need to change the resolving agent for access to both enantiomers of 1 and 2. ER -