Desymmetrizations of Diols
A new class of anionic, boron-bridged analogues of the box ligands was developed. These borabox ligands showed a considerable potential for asymmetric cyclopropanation and desymmetrizations of meso diols.
C. Mazet, V. Koehler, A. Pfaltz, Angew. Chem. Int. Ed., 2005, 44, 4888-4891.
A copper complex of a novel alicyclic chiral C2-symmetric piperazine allows the benzoylation of a series of cyclic and acyclic meso-1,2-diols to give optically active monobenzoates with high enantioselectivity.
D. Nakamura, K. Kakiuchi, K. Koga, R. Shirai, Org. Lett., 2006, 8, 6139-6142.
A phosphinite derivative that can be easily prepared in two steps from commercially available aminoindanol is an effective catalyst for enantioselective acylation of diols. For the asymmetric desymmetrization of meso-1,2-diols, the corresponding monoester was obtained in high enantioselectivity.
H. Aida, K. Mori, Y. Yamaguchi, S. Mizuta, T. Moriyama, I. Yamamoto, T. Fujimoto, Org. Lett., 2012, 14, 812-815.
A dinuclear asymmetric zinc catalyst has been applied for the desymmetrization of some meso diols. The best acyl transfer agent proved to be vinyl benzoate. Diacylation normally did not occur. A model to rationalize the results is presented.
B. M. Trost, T. Mino, J. Am. Chem. Soc., 2003, 125, 2410-2411.
A bench-stable chiral 9-hydroxy-9,10-boroxarophenanthrene catalyst is applied in a highly enantioselective desymmetrization of 2-aryl-1,3-diols using benzylic electrophiles under operationally simple, ambient conditions. Nucleophilic activation and discrimination of the enantiotopic hydroxy groups on the diol substrate occurs via a defined chairlike six-membered anionic complex.
C. D. Estrada, H. T. Ang, K.-M. Vetter, A. A. Ponich, D. G. Hall, J. Am. Chem. Soc., 2021, 143, 4162-4167.