One-pot thermally chemocontrolled double Diels-Alder strategies. A route to [4+2] functionalisation/[4+2] derivatization of C-60

The one-pot double Diels-Alder reactions of 3,4-di(methylene)tetrahydrothiophene-1,1-dioxide using temperature as the only chemocontrol element are described. Zn-dust promoted the 1,4-debromination of 3,4-bis(bromomethyl)-2,5-dihydrothiophene-1,1-dioxide in 5-nonanone, under MW conditions, followed by a Diels-Alder reaction, an SO2 extrusion step and a second Diels-Alder reaction. This approach was applied successfully in double [4 + 2] cycloadditions using the same or two different dienophiles to afford the corresponding Diels-Alder products in excellent yields. An elegant and practical method for [4 + 2] functionalisation/[4 + 2] derivatization of C-60 was achieved in a one-pot manner via the formation of a new reactive C-66 dienic intermediate. Rsc Advances