The Total Synthsis Of 5, 6-Dihydro-OSW-1 And The First Synthsis Of 5, 6-Dihydrogen Pennogenin

The Total Synthsis of 5, 6-Dihydro-OSW-1 and the First Synthsis of 5, 6-Dihydrogen PennogeninThe rational utilization of resource compounds is one main task of our research group. In order to make rational utilization of the abundant steroidal sapogenins, this dissertation is concerned on the syntheses of two products: 5, 6-Dihydro-OSW-1 and 5, 6-Dihydro Pennogenin, by utilizing the intact skeleton of tigogenin.First, the tigogenin has been acylated and oxidized by Oxone^R. Second, the compound 16, 22-diketon 36 can be obtained by opening the E, F-ring. Third, 16, 17-alkene 44 has produced by the debromination. Through the ethylene glycol ketal protection of 22-ketone, dihydroxylation of 16, 17-alkene function with O_sO₄, Swern oxidation of 16α-OH group, and stereoselective reduction of 16-keto to 16β-OH group, we have completed the synthesis of the protected aglycone of saponin 5, 6-Dihydro-OSW-1, which reacted with the disaccharide to afford the 5, 6-Dihydro-OSW-1.The full and rational utilization of the intact skeleton and functional groups of starting material has been used in the transformation of tigogenin to 5, 6-Dihydro pennogenin. Kroptgenin derivatives could be obtained from the oxidative-deketalization of tigogenin Similar strategy as synthesizing 5, 6-Dihydro-OSW-1 has been used to get 16, 22-diketo-17-ol. After deprotection of Ac group and acidification to provided 5, 6-Dihydropennogenin(65). Then 65 has been reacted with D-glucose to produce 5, 6-Dihydrogen pennogenin...