Base-catalyzed condensation of 2-hydroxybenzaldehydes with α,β-unsaturated aldehydes -: Scope and limitations

The base-catalyzed condensation of alpha,beta-unsaturated carbonyl compounds with 2-hydroxybenzaldehydes yielding tetrahydroxanthones and dihydrobenzopyrans has been investigated. A novel access to highly functionalized dihydrobenzopyrans via a mild generation of the dienol of senecialdehyde and subsequent conjugated aldol reaction has been reported.