Divergent Asymmetric Synthesis of Glutinosasins A–E

We report a divergent asymmetric synthesis of glutinosasins A–E. Glutinosasins A–D represent a novel subfamily of ent -kaurane diterpenoids characterized by their unprecedented 8,14- seco - ent -kaurane scaffold. The synthesis relies on several key steps: (a) a Baran reductive olefin coupling to establish a trans -decalin framework containing a C10 quaternary center; and (b) a Lewis acid-mediated deprotection/retro-Claisen condensation cascade to construct the 8,14- seco - ent -kaurane scaffold. We have developed a stereodivergent strategy for constructing decalin frameworks, where a C7-sp 3 substrate delivers a trans -decalin structure, while a C7-sp 2 substrate provides a cis -decalin configuration. This approach can be extended to the synthesis of related natural products containing either cis - or trans -decalin motifs.