One-pot thermally chemocontrolled double Diels–Alder strategies. A route to [4 + 2] functionalisation/[4 + 2] derivatization of C60

Abstract

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 C₆₀ was achieved in a one-pot manner via the formation of a new reactive C₆₆ dienic intermediate.