Enantioselective constructions of quaternary carbons and their application to the asymmetric total syntheses of fredericamycin A and discorhabdin A*
Yasuyuki Kita and Hiromichi Fujioka
Faculty of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565, Japan
Abstract: An efficient enantioselective construction of quaternary carbons including spiro carbons is an area of intense interest due to the importance of these units as components of biologically active natural products. Prominent methods are presented for the synthesis of chiral, nonracemic quaternary carbon centers by (i) stereospecific rearrangement of optically active epoxides, (ii) enzyme-catalyzed resolution, and (iii) hypervalent iodine reagent-induced ipso-substitution of para-substituted phenol derivatives. These methods were applied to the total syntheses of fredericamycin A and discorhabdin A.
Keywords: asymmetric synthesis; quaternary carbons; spiro carbons; fredericamycin A; discorhabdin A.
*Pure Appl. Chem. 79, 467-823 (2007) pp. 467-823. An issue of reviews and research papers based on lectures presented at the 25th International Symposium on Chemistry of Natural Products (ISCNP-25) and 5th International Conference on Biodiversity (ICOB-5), held jointly in Kyoto, Japan, 23-28 July 2006, on the theme of natural products.