Abstract
Abstract The thesis consists of two parts: the first part details with the application of perhydoindolone 141 in the total synthesis of (±)-lentiginosine (1) and the second part describes the Diels-Alder reactions of perhydoindolone 90 and it’s synthetic application to the ABC tricyclic skeleton of manzamine A. In the chapter 1, the total synthesis of (±)-lentiginosine (1) is presented. The key starting material perhydoindolone 141 was synthesized from compound 140 via anionic cyclization. Compound 141 was then reduced with NaBH4, followed by protection and ozonalysis to give ketoaldehyde 144. The transformation of ketoaldehyde 144 into compound 153 was achieved by three functional group manipulations. Cleavage of the t-Boc protecting group in 153 followed by cyclization under basic condition afforded the bicyclic compound 154. Finally, deprotection of compound 154 with TBAF in THF finished the synthesis of (±)-lentiginosine (1). The second chapter described the Diels-Alder reactions of perhydoindolone 90 and synthetic study to the ABC tricyclic skeleton of manzamine A. Compound 118 was obtained by Diels-Alder reaction of 90 with 2-triethylsilyloxy-1,3-butadiene 117. Oxidation of the enol moiety in 118 under Rubottom condition followed by oxidative cleavage and Jones oxidation afforded acid 121. The key compound 122 was then obtained by Curtius rearrangement. Further efforts have to be made to utilize the compound 122 for the synthesis of the tricyclic core of manzamine A.