Total Synthesis of (−)-Calyciphylline N

The total synthesis
of the architecturally complex Daphni­phyllum alkaloid (−)-calyci­phylline N has been achieved. Highlights
of the synthesis include a Et2AlCl-promoted, highly stereo­selective,
susbtrate-controlled intramolecular Diels–Alder reaction, a
transannular enolate alkylation, an effective Stille carbonylation/Nazarov
cyclization sequence, and a high-risk diastereo­selective hydrogen­ation
of a fully substituted conjugated diene ester.