Intramolecular Friedel-Crafts Reaction Of α-Hydroxy Ketene-(S,S)-Acetals For The Synthesis Of Polysubstituted Indenes

From the point of structure, α-Hydroxyl ketene-(S,S)-acetals belong tomultifunctional allyl alcohol, they can be used in the dehydration reaction,etherification, the cleavage of carbon-carbon, Ritter etc. And they can be synthesizedconveniently from the reduction of α-oxo ketenedithioacetals. The application ofα-Hydroxyl ketene-(S,S)-acetals has become an important research in the area oforganic synthesis.On the basis of our previous research, the intramolecular Friedel-Crafts reactionof α-hydroxyl ketene-(S,S)-acetals under the catalysis of anhydrous FeCl3has beenexplored, from which we have obtained a series of polysubstituted indene derivatives.Polysubstituted indenes are effective structure fragments of varies drugs bearingbiological activities and functional materials. A new method to synthesizepolysubstituted indenes has been discovered. The specific content are as follows:First, a series of α-hydroxyl ketene-(S,S)-acetals were obtained easily from thereduction of α-oxo ketenedithioacetals under NaBH4.Second, a facile method has been discovered to synthesize polysubstitutedindenes by Friedel-Crafts reaction of α-hydroxyl ketene-(S,S)-acetals under thecatalysis of anhydrous FeCl3.