CuI-Mediated Synthesis of Sulfonyl Benzofuran-3-ones and Chroman-4-ones

Abstract

A concise, one-pot synthesis of sulfonyl benzofuran-3-ones and chroman-4-ones from α-sulfonyl o-hydroxyacetophenones is described, using a combination of KCO, CuI, and dimethylsulfoxide (DMSO). This annulation protocol generates one carbon-oxygen (C-O) bond and one carbon-carbon (C-C) bond in a highly efficient manner.

Construction of Sulfonyl Dihydrobenzo[c]xanthen-7-ones Core via NH4OAc/PdCl2/CuCl2-Mediated Double Cyclocondensation of α-Sulfonyl o-Hydroxyacetophenones with 2-Allylbenzaldehydes

“…Required starting materials 2 were easily prepared from o -hydroxyacetophenones following a procedure in literature that included α-bromination of o -hydroxyacetophenones followed by the nucleophilic substitution of the resulting α-bromo- o -hydroxyacetophenones with RSO 2 Na. To examine the formation of the dihydrobenzo­[ c ]­xanthen-7-one core, our research began on the reaction of model compounds 2a (R = Tol, Ar′ = Ph, 0.5 mmol) and 3a (Ar = 3,4-(MeO) 2 Ph, 0.5 mmol) with the NH 4 OAc (0.8 equiv) in MeOH (3 mL) at reflux for 5 h. 3-Sulfonyl flavanone 4a was isolated as a sole isomer in a 92% yield under the Knoevenagel condensation conditions.…”

Efficient synthesis of benzo[h]carbazol[3,2‐b][1,6]naphthyridines

“…As a result of this, the amination of aryl halides by CuI has received a lot of attention. Tandem annulations, a unique combination of copper(I)iodide, and dimethylformamide have piqued interest due to their ease of use and strong reactivity [13,14].…”

Bi(OTf)3‐Mediated (4+1) Annulation of α‐Sulfonyl o‐Hydroxyacetophenones with α‐Hydroxy Arylketones to Access Sulfonyl 2‐Aroylbenzofurans

“…Among bismuth(III) salts, [25–27] Bi(OTf) 3 belongs to a group of efficient and environmentally benign promoters for catalysing various functional group transformations and establishing carbon‐carbon/carbon‐heteroatom bond formations. In continuation of the recent research on a diverse set of Bi(OTf) 3 ‐promoted reactions [28–31] and the related synthetic applications of α‐sulfonyl o ‐hydroxyacetophenones, [32–33] we present a Bi(OTf) 3 ‐mediated one‐pot (4+1) annulation route (called the Rap‐Stoermer reaction) to 3‐sulfonylmethyl 2‐aroylbenzofurans; this route involves intermolecular double cyclocondensation of α‐sulfonyl o ‐hydroxyacetophenones with substituted α‐hydroxy arylketones and the formation of one carbon‐carbon double (C=C) bond and one carbon‐oxygen single (C−O) bond (green bonds, Scheme 1).…”