Novel transformation of 2-substituted alkyl 1-indnone-2-acetates to 6-substituted 3,4-benzotropolones through sequential reduction and oxidation processes using Sm(II)and Ce(IV)salts

摘要

When 2-substituted alkyl 1-indanone-2-acetates 1 were treated with samarium diiodide,3-substituted 2-hydroxy-2,3-methanol-1-oxo-1,2,3,4-tetrahydronaphthalenes 4 were obtained.The reaction is proposed to proceed through a rearrangement initiated by intramolecular ketone-ester coupling.Oxidation of these products 4 or their silyl ethers 13 by ceric(IV)ammonium nitrate involving regioselective bond cleavage of their bicyclo[4.1.0]-rings produced the corresponding benzotropolone derivatives 10.