EnantioselectiveTotal Synthesis of Fortalpinoid Qvia a TEMPO⁺BF₄^–‑MediatedDehydrative Nazarov Cyclization

The family of <i>Cephalotaxus</i> diterpenoids represents a captivating class of natural products that are of significant interest from both structural and biological perspectives within our community. Here we wish to report a 15-step, enantioselective total synthesis of the <i>Cephalotaxus</i> diterpenoid fortalpinoid Q. Our approach highlights (1) a Jacobsen’s catalytic enantioselective Claisen rearrangement that enabled the single-step formation of two vicinal stereogenic centers, including an all-carbon quaternary center; (2) a mild, oxoammonium salt (TEMPO⁺BF₄^–)-promoted dehydrative Nazarov cyclization that swiftly forged the crucial cyclopentadiene moiety via an unfunctionalized tertiary divinyl carbinol (TDC) substrate; and (3) a facile aldol-lactonization cascade that ultimately resolved the last obstacle in the synthesis.