A novel route to preussomerins via 2-arylacetal anions.

[reaction--see text] Dimerization of salicylaldehydes provided 6H,12H-6,12-epoxydibenzo[b, f][1,5]dioxocins in multigram quantities. Deprotonation-allylation of the benzylic acetals followed by further functionalization of the diallyl derivative and double Friedel-Crafts cyclization gave a novel preussomerin analogue which possessed the full carbon skeleton of the natural products.