A Comparative Study in Oxidative Free Radical Reactions between 9- Benzylidene-9-H Fluorene Derivatives and β-Dicarbonyl Compounds in the Presence of Mn(OAc)3 and CAN

The reactions of some 1,3-dicarbonyl compounds with 9-benzylidene-9-H-fluorene derivatives in the presence of manganese(III)acetate and ceric ammonium nitrate (CAN) were searched. 9-benzylidene-9-H-fluorene compounds form mainly [2+3] dipolar cycloaddition products such as dihydrofuran and lactone which are spirally attached to the C-9 position of flourene ring with manganese(III)acetate and oxidative addition products with CAN. The best yield of cyclization products was obtained from the reaction between 2c and 1a-c in both oxidants. The stereochemistry of the products 3d, 4d and 5d was only transformed which has coupling constant 13 Hz.