Chemoselective Intermolecular α‐Arylation of Amides

Peng, Bo; Geerdink, Danny; Farès, Christophe; Maulide, Nuno

doi:10.1002/anie.201402229

Cited by 174 publications

(67 citation statements)

References 91 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Recently, we34353637383940 and others41424344454647484950515253545556 reported the metal-free, sulfoxide directed57 C–H functionalization of a variety of molecular scaffolds, which was enabled by an interrupted Pummerer reaction28. Spurred on by these recent achievements, we considered the use of benzothiophene S -oxides 1 for the synthesis of important C3-functionalized benzothiophenes, as the corresponding sulfonium salts I and II , formed after reaction with the coupling partners, lack aromaticity about the five-membered ring and should therefore undergo facile C–C bond formation via [3,3]-sigmatropic rearrangement58, thus delivering unexplored reactivity not accessible in benzothiophenes.…”

Section: Resultsmentioning

confidence: 99%

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

et al. 2017

View full text Add to dashboard Cite

Benzothiophenes are heterocyclic constituents of important molecules relevant to society, including those with the potential to meet modern medical challenges. The construction of molecules would be vastly more efficient if carbon–hydrogen bonds, found in all organic molecules, can be directly converted into carbon–carbon bonds. In the case of elaborating benzothiophenes, functionalization of carbon–hydrogen bonds at carbon-number 3 (C3) is markedly more demanding than at C2 due to issues of regioselectivity (C3 versus C2), and the requirement of high temperatures, precious metals and the installation of superfluous directing groups. Herein, we demonstrate that synthetically unexplored but readily accessible benzothiophene S-oxides serve as novel precursors for C3-functionalized benzothiophenes. Employing an interrupted Pummerer reaction to capture and then deliver phenol and silane coupling partners, we have discovered a directing group-free method that delivers C3-arylated and -alkylated benzothiophenes with complete regioselectivity, under metal-free and mild conditions.

show abstract

Section: Resultsmentioning

confidence: 99%

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Given our ongoing interest in metal-free a-arylation of bketo esters [11] and amides, [12] we sought to develop chiralitytransfer strategies.H owever,i ni nitial efforts (Scheme 1B), the use of chiral sulfoxide 6afor the arylation of b-ketoester 5 met with failure,s ince only racemic product 7 was obtained despite several attempts. [13] We ascribe this disappointing result to configurational instability of the sulfur center during the reaction.…”

mentioning

confidence: 99%

An Asymmetric Redox Arylation: Chirality Transfer from Sulfur to Carbon through a Sulfonium [3,3]‐Sigmatropic Rearrangement

et al. 2017

Self Cite

View full text Add to dashboard Cite

A general, asymmetric redox arylation of ynamides and thioalkynes with chiral sulfoxides is reported. This is the first example of a general 1,4-chirality transfer from sulfur to a carbon stereocenter through a sulfonium [3,3]-sigmatropic rearrangement. This reaction delivers α-arylated thioesters and amides under mild conditions in an atom-economical manner. The products are formed in high yields with enantiomeric ratios up to 99.5:0.5. Quantum chemical calculations suggest a mechanism for the chirality transfer from sulfur to carbon and explain the experimentally observed correlation of the enantioselectivity with both the catalyst and the substrate.

show abstract

“…Maulide and co-workers showed that aryl sulfoxides 53 can undergo ortho CÀHa lkylation upon treatment with activated amides (Scheme 35). [53] Thea mides were activated with triflic anhydride in the presence of 2-iodopyridine and formed iminium dications 88 via iminium triflates.E ither iminium dication 88 or keteniminium triflate 89 reacts with the nucleophilic sulfoxide oxygen atom to form sulfonium salt 90,w hich can undergo a [ 3,3]-sigmatropic rearrangement. This CÀH/CÀHcoupling reaction has abroad scope and even allows for the coupling of hindered amides and, impressively, the selective a-arylation of amides in the presence of esters and ketones.…”

Section: Reactions Of Sulfoxides With Electrophilic Coupling Partnersmentioning

confidence: 99%

C−H Coupling Reactions Directed by Sulfoxides: Teaching an Old Functional Group New Tricks

2016

View full text Add to dashboard Cite

Sulfoxides are classical functional groups for directing the stoichiometric metalation and functionalization of C-H bonds. In recent times, sulfoxides have been given a new lease on life owing to the development of modern synthetic methods that have arisen because of their unique reactivity. They have recently been used in catalytic C-H activation proceeding via coordination of an internal sulfoxide to a metal or through the action of an external sulfoxide ligand. Furthermore, sulfoxides are able to capture nucleophiles and electrophiles to give sulfonium salts, which subsequently enable the formation of C-C bonds at the expense of C-H bonds. This Review summarizes a renaissance period in the application of sulfoxides arising from their versatility in directing C-H functionalization.

show abstract

Chemoselective Intermolecular α‐Arylation of Amides

Cited by 174 publications

References 91 publications

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

An Asymmetric Redox Arylation: Chirality Transfer from Sulfur to Carbon through a Sulfonium [3,3]‐Sigmatropic Rearrangement

C−H Coupling Reactions Directed by Sulfoxides: Teaching an Old Functional Group New Tricks

Contact Info

Product

Resources

About