Two Total Syntheses of Trigoxyphins K and L

Two total syntheses are presented for trigoxyphins K and L, tricyclic terpenoids from Trigonostemon xyphophylloides. The first proceeds via electrophlic cyclization in A/C-ring substrates to close the B ring at C4-C5 and then O-1(2)-mediated hydroxybutenolide formation to trigoxyphin L, with Luche reduction leading to trigoxyphin K. The second route develops from tetralone ring expansion to a B/C-ring intermediate that, by one-step O-demethylation-lactonization-isomerization, affords trigoxyphin K and then trigoxyphin L following enolate oxygenation.

Automated summary

Two total syntheses for trigoxyphins K and L, tricyclic terpenoids from Trigonostemon xyphophylloides, are presented. The first synthesis involves electrophlic cyclization and hydroxybutenolide formation to produce trigoxyphin L, followed by Luche reduction to obtain trigoxyphin K. The second synthesis employs tetralone ring expansion and lactonization-isomerization to yield trigoxyphin K, which is then converted to trigoxyphin L through enolate oxygenation.