作者:Frank E. McDonald、Mary A. Smart
DOI:10.3987/com-12-s(n)51
日期:——
The tetracyclic skeleton of thyrsenols A and B has been assembled, with the construction of ring A by exo-selective oxacyclization of an epoxybromohydrin, B ring formation by exo-selective oxacyclization of hydroxyepoxide followed by solvolytic ring expansion of a tetrahydrofuran to tetrahydropyran, C ring closure by tungsten-promoted endo-selective oxacyclization of a hydroxyalkyne, and D ring preparation by asymmetric dihydroxylation of an epoxyalkene accompanied by exo-selective oxacyclization. A modified Stille coupling linked two fragments at C-14-C-15 to directly provide the tetracyclic dienylether.