A reaction that takes to water: The domino Michael addition/aldol condensation of salicylic aldehydes like 1 as the nucleophile and 2‐cyclohexen‐1‐one (2) as the Michael acceptor provides 2,3,4,4a‐tetrahydroxanthen‐1‐ones such as 3 in good yields. DABCO=1,4‐diazabicyclo[2.2.2]octane.

Die Verwendung von Wasser bei der Domino‐Michael‐Addition‐Aldolkondensation von Salicylaldehyden wie 1 als Nucleophil und Carbonylkomponenten wie 2‐Cyclohexen‐1‐on (2) als Michael‐Acceptor liefert 2,3,4,4a‐Tetrahydroyxanthen‐1‐one wie 3 in sehr guten Ausbeuten.

The base-catalyzed condensation of a,b-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.

Tetrahydroxanthenones, which can be easily prepared by a domino oxa-Michael aldol condensation, offer various possibilities for diastereoselective functionalization, giving access to the stereocontrolled synthesis of stereochemical triades or tetrades, which represent privileged structural motifs. In most cases, the relative stereochemistry was unequivocally established by crystal structure analysis.

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