Photocatalytic Markovnikov-type addition and cyclization of terminal alkynes leading to 4-sulfonyl quinoline-2(1)-ones.

A new and expedient photocatalytic protocol for the construction of quinolin-2(1)-ones Markovnikov-type sulfonylation/6-endo-trig cyclization/selective C(O)-CF bond cleavage starting from -alkyl--(2-ethynylphenyl)-2,2,2-trifluoroacetamides and sulfinic acids has been developed. It is as an unprecedented protocol for the preparation of 4-sulfonylquinoline-2(1)-ones with high efficiency, mild reaction conditions, acceptable yields and a wide range of substrates.