Photochemical Functionalization of 4-Diazoisoquinoline-1,3(2<i>H</i>,4<i>H</i>)-diones and Their 1-Sulfoxide Analogues

Isoquinoline-1,3-(2<i>H</i>,4<i>H</i>)-diones have been the subject of numerous studies toward new pharmaceuticals, and therefore novel, mild functionalizations of this scaffold are highly desirable. As diazo compounds are versatile reagents in organic synthesis, 4-diazoisoquinoline-1,3-(2<i>H</i>,4<i>H</i>)-diones should give access to a broad range of various derivatives. Indeed, they enable the introduction of fluorinated moieties via photochemical O-H insertion reactions in serviceable yields, typically in under 2 h. Exchanging the 1-carbonyl group with the sulfoxide moiety causes a hypsochromic shift in the absorption of the diazo compounds, and thus, violet light is required for effective O-H and S-H insertion reactions.