Novel Synthesis Of γ-lactones And 3, 3-difluoro-2-oxindoles Via Visibie Light Photocatalysis

Photoredox catalysis via visible light can reduce the limitation of substrates and improve the chemoselectivity of photo-reaction, which could utilize solar energy into chemical synthesis directly and become one of highlights in area of organic chemistry recent years. This thesis is about visible light photoredox catalysis:applications in organic synthesis. We developed several useful organic reactions via visible-light photoredox catalysis and studied the mechanism of these reactions via looking for new reaction system of visible-light photoredox catalysis. As below:First, by using commercially available styrene and a-bromo esters under irradiation of 3 W blue LEDs light with 0.5 mol% fac-Ir(ppy)3 as photocatalys and inorganic salt LiBF4 as an additive, the aimed γ-lactones can be obtained with high yields and excellent regioselectivity at room temperature. Photoluminescence quenching experiments and H218O labeling experiment indicates reductive quenching plays important roles in the photoredox catalytic cyclesSecond, withy fac-Ir(ppy)3 as photocatalys and base K2HPO4 as additive, under irradiation of 3 W blue LEDs light by using simple and easily synthesized substrates, the aimed difliioroxindole can be obtained smoothly. This reaction can be achieved with good yields without the application of transition mental or harsh reaction conditions.