Asymmetric Epoxidation of α-Olefins Having Neighboring Sugar Chiral Templates and Alternating Copolymerization with Dicarboxylic Anhydrides

Sugar-substituted epoxides 5-8 were synthesized by asymmetric epoxidation (in CH 2 Cl 2 /water) of α-olefins having neighboring sugars (1-4) by use of an achiral oxidant (MCPBA), in which the sugar moiety acted as a chiral template. The diastereoselectivities depend on the methylene spacer between vinyl group and carbohydrate derivatives. The methylene spacer between sugar and vinyl groups influenced the diastereo-selectvity. In the case of epoxidation of 4 at 27 °C for 24 h, the diastereoselectivity was the highest (99/1). Copolymerizations of 5-8 with succinic anhydride were attained at 100 °C for 72 h to give poly(ethylene succinate) having pendant carbohydrate [poly(SAn-alt-5), M n = 1.4 x 10 3 ; poly(SAn-alt-6), M n = 2.2 x 10 3 ; poly(SAn-alt-7), M n = 2.9 x 10 3 ; poly(SAn-alt-8), M n = 1.8 x 10 3 ]. The methylene spacer between sugar and epoxide has an effect on the reactivity of epoxide in copolymerization as well as the diastereoselectivity. Alternating copolymerization of 7 and glutaric anhydride gave a polyester of M n 4.2 x 10 3 .