Copper-catalyzed α-benzylation of BODIPYs via radical-triggered oxidative cross-coupling of two C–H bonds

An oxidative cross-dehydrogenative coupling of BODIPYs with toluene and its derivatives has been developed, allowing for the facile synthesis of a broad range of structurally diverse α-benzylated BODIPYs. The method exhibits excellent chemoselectivity, affording exclusively α-benzylated BODIPYs in the presence of t-BuOOH and a catalytic amount of Cu(OAc)2. The direct use of readily available toluene and its derivatives as coupling partners avoids unproductive steps for preactivating the functional group installation, and is therefore attractive. Most of the resulting dyes are highly emissive in the solid state due to the introduction of bulky benzyl groups onto the BODIPY core.