Asymmetric Total Synthesis of (+)-21-epi-Eburnamonine Via a Photocatalytic Radical Cascade Reaction

An asymmetric total synthesis of(+)-21-epi-eburnamonine has been achieved.Key features of the synthesis include a visible-light photocatalytic intra-/intramolecular radical cascade reaction to assemble the tetracyclic ABCD ring system,and a highly diastereoselective Johnson-Claisen rearrangement to establish the C20 all-carbon quaternary stereocenter.

Efficient and collective total synthesis of natural products via radical cascade reactions

Subject Code:B02With the support of the National Natural Science Foundation of China,the research team led by Prof.Qin Yong(秦勇)at Sichuan University accomplished a collective synthesis of 33 monoterpenoid indole alkaloids that belong to four families,by developing new photoredox-initiated radical cascade reactions.

Visible-light-induced radical-cascade alkylation/cyclization of N-methacryloyl-2-phenylbenzimidazole:Access to benzoimidazo[2,1-a]isoquinolin-6(5H)-ones

A metal-free visible-light-induced synthesis of aza-polycyclic aromatic hydrocarbons via cascade alkylation/cyclization of N-methacryloyl-2-phenylbenzimidazole was developed.The reaction was carried out with inactive alkanes and cyclic ethers as alkylation reagents,and phenanthrenequinone(PQ)as a direct hydrogen-atom transfer(HAT)photocatalyst.The desired products were obtained in moderate to good yields at room temperature under air.

Metal-free photo-induced radical C-P and C-S bond formation for the synthesis of 2-phosphoryl benzothiazoles

We reveal here a visible-light promoted phosphorylation of 2-isocyanoaryl thioethers for the first time with concomita nt C(sp3)-S bond cleavage and imidoyl C-S fo rmation.Additionally,this method features the use of 3 mol%organic dye Rose Bengal as the photocatalyst without external transition-metal or peroxide oxidants,and provides a novel and environmentally friendly approach for the preparation of a variety of 2-phosphoryl benzothiazoles in moderate to good yields.