Hypervalent iodine-guided electrophilic substitution: para-selective substitution across aryl iodonium compounds with benzyl groups

• Cyrus Mowdawalla,
• Faiz Ahmed,
• Tian Li,
• Kiet Pham,
• Loma Dave,
• Grace Kim and
• I. F. Dempsey Hyatt

Beilstein J. Org. Chem. 2018, 14, 1039–1045, doi:10.3762/bjoc.14.91

• -withdrawing groups could also explain how the carbonyl of the cyclic iodonium (3) caused that specific reagent to fail (Table 1, entries 6 and 7). Several para-substituted I(III) reactants were attempted but all led to complex mixtures with the exception of the diaryliodonium triflate 2d (Table 2, entry 3

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

• the preparation of heterocyclic compounds [43][44][45][46], we would like to report an efficient one-pot preparation of 4-aryl-3-bromocoumarins by treatment of 3-aryl-2-propynoic acids with diaryliodonium triflate in the presence of a base, followed by the reaction with tetrabutylammonium bromide

• ) 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