Application of intramolecular carbonyl-ene reaction towards the synthesis of idarubicinone scaffold

Intramolecular aromatic carbonyl-ene reaction (ICE)(dagger )has been combined with a modified Hauser annulation to offer a facile access to the tetracyclic idarubicinone core. The required key dihydroxyanthraquinone aldehyde precursor was assembled in one step by modified Hauser annulation of a functionalized benzoquinone. Its ene reaction in the presence of SnCl4 center dot 5H(2)O directly led to the formation of idarubicinone core. Also described are an unprecedented thermal cascade involving a thermal ICE en route to alpha-naphthols, and exploratory studies on model elaboration of anthracycline A rings. [GRAPHICS] .