Chen, Pu; Chen, Zan; Xiong, Bi-Quan; Liang, Yun; Tang, Ke-Wen; Xie, Jun; Liu, Yu published their research in Organic & Biomolecular Chemistry in 2021. The article was titled 《Visible-light-mediated cascade cyanoalkylsulfonylation/cyclization of alkynoates leading to coumarins via SO2 insertion》.Formula: C33H24IrN3 The article contains the following contents:
A visible-light-mediated tandem cyanoalkylsulfonylation/cyclization of alkynoates with cycloketone oxime compounds for the preparation of 3-cyanoalkylsulfonylcoumarins I [R1 = H, 6-Me, 7-OMe, etc.; R2 = Me, Ph, 2-thienyl, etc.; R3 = H, Ph, 4-MeC6H4, etc.; R4 = H, Me; R5 = H, Bn] via SO2 insertion was reported. The difunctionalization of carbon-carbon triple bonds includes a radical mechanism and involved the formation of an iminyl radical, ring-opening of the cycloketone, insertion of SO2, addition of the sulfonyl radical to carbon-carbon triple bonds, ipso-cyclization and ester migration. In the experiment, the researchers used many compounds, for example, fac-Tris(2-phenylpyridine)iridium(cas: 94928-86-6Formula: C33H24IrN3)
fac-Tris(2-phenylpyridine)iridium(cas: 94928-86-6) belongs to pyridine. Pyridine is very deactivated towards electrophilic substitution with respect to benzene. For this reason classical formylation, using methods such as the Gattermann or Vilsmeier reactions, are not generally successful. Formula: C33H24IrN3