Pursuing high efficiency in photocatalytic oxidative couplings of heteroarenes and aliphatic C-H bonds

5- and 6-membered heteroarenes, both azoles and azines, were directly alkylated by alkanes, ethers and carbamates using t-butyl peroxybenzoate under LED irradiation. As a serendipitous finding, an organic photosensitizer, 9,10-dichloroanthracene, significantly increased overall efficiency of radical couplings via energy transfer of exciplexes and allowed many examples of oxidative couplings to proceed in good yields, even when 1.5 equivalents of alkanes were used.