Synthesis and its application to the synthesis of biologically active natural products of new and versatile chiral building blocks

This article describes a design and synthesis of new and versatile chiral b uilding blocks and its application to the biologically active natural produ ct synthesis. The chiral building blocks were prepared using a biocatalysis in an enantiomerically pure state. As an application of the above chiral b uilding blocks to the synthesis of biologically active natural product, we demonstrated the diastereodivergent synthesis of the 3-piperidinol alkaloid s cassine, spectaline, prosafrinine, iso-6-cassine, prosophylline, prosopin ine, and also established the flexible route to the 5,8-disubstituted indol izidine or 1,4-disubstituted quinolizidine type of Dendrobates alkaloids. A s another application to the synthesis of biologically active alkaloids, we accomplished the first enantioselective total synthesis of marine alkaloid s clavepictines A, B, and pictamine using a highly stereoselective Michael type quinolizidine ring closure reaction as the crucial step, and the first total synthesis of a marine alkaloid lepadin B was also achieved using ald ol cyclization controlled by a A((1.3)) strain.