Organic chemistry

Enzyme

Cleave

Combinatorial chemistry

Methylation

Stereochemistry

Biology

Radical

Catalysis

Medicinal chemistry

Copolymer

Chemistry

Ecology

Organic peroxide

Substrate (aquarium)

Molecule

Alkyl

Peroxide

Aryl

Polymer

Biochemistry

Photochemistry

Science

Adding methyl groups with good timing In pharmaceutical research, swapping out hydrogens for methyl groups is a frequent strategy to optimize small-molecule properties. Vasilopoulos et al. report a versatile, convenient, and comparatively safe method for methylation of carbon centers adjacent to nitrogen or aryl rings. Under carefully optimized conditions, di-tert-butyl peroxide plays a dual role as oxidant and methyl source. Cleaving the O–O bond through photosensitization produces butoxyl radicals, some of which cleave substrate C–H bonds, whereas others release methyl radicals that a nickel catalyst delivers to those activated substrates. Science , this issue p. 398

C(sp <sup>3</sup> )–H methylation enabled by peroxide photosensitization and Ni-mediated radical coupling

C(sp 3 )–H methylation enabled by peroxide photosensitization and Ni-mediated radical coupling

C(sp ³ )–H methylation enabled by peroxide photosensitization and Ni-mediated radical coupling