Synthesis of functionalized chromans by PnBu3-catalyzed reactions of salicylaldimines and salicylaldehydes with allenic ester.

P(n)Bu(3)-catalyzed cyclization reactions of salicylaldimines and salicylaldehydes with ethyl 2,3-butadienoate gave the corresponding functionalized chromans in moderate to good yields in THF under mild conditions. The new reaction provides a new method for the synthesis of biologically active chroman products.