One-pot preparation of 4-aryl-3-bromocoumarins from 4-aryl-2-propynoic acids with diaryliodonium salts, TBAB, and Na₂S₂O₈

• Teppei Sasaki,
• Katsuhiko Moriyama and
• Hideo Togo

Beilstein J. Org. Chem. 2018, 14, 345–353, doi:10.3762/bjoc.14.22

• transformed into 4-phenylcoumarin derivatives bearing C–H, C–S, C–N, and C–C bonds at 3-position. Keywords: 3-aryl-2-propynoic acid; bromo-cyclization; coumarin; diaryliodonium triflate; O-phenylation; Introduction Coumarin is a benzo-α-pyrone and one of the typical heterocyclic compounds. The importance of

• ) with di(p-chlorophenyl)iodonium triflate (D) and then with TBAB and Na2S2O8, was carried out, as shown in Figure 1. Based on those results, the possible reaction pathway is shown in Scheme 4. The O-arylation of 3-aryl-2-propynoic acid 1 with diaryliodonium triflate in the presence of K2CO3 and CuCl