Copper/Silver-Mediated Cascade Reactions for the Construction of 2-Sulfonylbenzo[b]furans from trans-2-Hydroxycinnamic Acids and Sodium Sulfinates

Abstract

Efficient construction of 2-sulfonylbenzo[b]furans is achieved from readily available trans-2-hydroxycinnamic acids and sodium sulfinates mediated by the CuCl2·2H2O/AgTFA system under mild conditions. This unprecedented synthetic protocol provides expedient access to a series of products in one step via a protodecarboxylation/C-S bond formation/C-O bond formation cascade.

Palladium‐Catalyzed C−H Functionalization of Phenyl 2‐Pyridylsulfonates

“…7‐Phenyl‐2‐(phenylsulfonyl)benzofuran (7 vf) : Prepared according to the general procedure as a white solid (18.4 mg, obtained from 0.1 mmol corresponding alkenlated phenyl 2‐pyridinesulfonate, 55 %) after purification by flash column chromatography using a mixture of petroleum ether and ethyl acetate (4:1 v/v). m.p.=240–241 °C.…”

Synthesis and applications of sodium sulfinates (RSO2Na): a powerful building block for the synthesis of organosulfur compounds

“…The cascade decarboxylation reaction proceeded via tandem C–S and C–O bonds formation under mild conditions ( Scheme 198 ). 305 A variety of aromatic and aliphatic sulfinates easily reacted with trans -2-hydroxycinnamic acids, whereas the scope of trans -2-hydroxycinnamic acids was well-tolerated to give a series of 2-sulfonylbenzo[ b ]furan derivatives in moderate to good yields. Meanwhile, benzofuran-2-carboxylic acid treated with sodium sulfinates under the same conditions did not produce the expected 2-sulfonylbenzo[ b ]furans.…”

Oxidative Sulfonylation of Multiple Carbon‐Carbon bonds with Sulfonyl Hydrazides, Sulfinic Acids and their Salts

“…2‐Sulfonyl substituted benzofurans 488 were obtained from 2‐hydroxycinnamic acids 486 and sodium alkyl and aryl sulfinates 487 in the presence of CuCl 2 ⋅ 2H 2 O/AgTFA and Cs 2 CO 3 in DMF at 80–100 °C under air (Scheme 212). [264] …”