Application Of Allylsilanes In The Total Synthesis Of Sesquiterpenes And Spiroketal Construction By Ni(0)-catalyzed Annulation

This thesis aims at the applications of allylsilanes in total synthesis of triquinanes. Our work includes the dual total synthesis of (±)-Hirsutene and (±)-Capnellene, novel allylsilane annulation approach towards eudesmane, and construction of spiroketals catalyzed by BMAP-Ni(0) complex. It consists of the following four parts.Chapter1:The character of linear triquinanes and the synthetic studies on (±)-Hirsutene and (±)-Capnellene were summarized in this chapter.Chapter2:The details of a new versatile approach toward the dual total synthesis of (±)-Hirsutene and (±)-Capnellene based on homoiodo allylsilanes are described. This general synthetic sequence involves an enolate alkylation of homoiodo allylsilanes and subsequent intramolecular cyclization of allylsilanes. Chapter3:An anomeric effects-controlled and stereoselective synthesis of [5,5] and [5,6]-spiroketals (and aminals) via tandem cyclization-Michael addition of P-haloketals catalyzed by BMAP-Ni(0) complex is described. This methodology also allows successful construction of [5,5,5]-bis-spiroketal and spiroketal-perhydrofluro [2,3-b]furan (and pyran) hybrid.Chapter4:A novel facile annulation approach was developed towards the synthesis of eudesmane framework. This approach involves the Ni(0)-mediated coupling reaction of homoiodo allylsilanes with methyl acrylate and a subsequent cyclization of allylsilane function with aldehyde.