Studies directed to the total synthesis of biologically active natural products
The total synthesis of biologically active, naturally occurring substances is an ambitious task. Fascinating new methods have been developed for the synthesis of natural products. We discuss the following accomplishments: (1) The short and convergent synthesis of 4,1-Bisdeoxydaunamycinone by Claisen/Diels-Alder sequence. (2) The regiochemical studies on the Diels-Alder reaction of electron-rich dienes and activated dienophiles, and the effort toward the aza-tricyclic moiety of atisine-type alkaloids. (3) The formation of bicyclic and monocyclic intermediates via silyl radical induced cyclizations, and the first chemoselective studies on silicon radicals.