70445-87-3Relevant academic research and scientific papers
Chiral Benzothiophene Synthesis via Enantiospecific Coupling of Benzothiophene S-Oxides with Boronic Esters
Aggarwal, Varinder K.,Noble, Adam,Sang, Ruocheng
supporting information, p. 25313 - 25317 (2021/11/09)
Benzothiophenes are valuable heterocycles that are widely used in medicines, agrochemicals, and materials science. Herein, we report a general method for the synthesis of enantioenriched 2,3-disubstituted benzothiophenes via a transition-metal-free C2-alkylation of benzothiophenes with boronic esters. The reactions utilize benzothiophene S-oxides in lithiation-borylations to generate intermediate arylboronate complexes, and subsequent Tf2O-promoted S?O bond cleavage to trigger a Pummerer-type 1,2-metalate shift, which gives the coupled products with complete enantiospecificity. Primary, secondary and tertiary alkyl boronic esters and aryl boronic esters are successfully coupled with a range of C3-substituted benzothiophenes. Importantly, this transformation does not require the use of C3 directing groups, therefore it overcomes a major limitation of previously developed transition-metal-mediated C2 alkylations of benzothiophenes.
Para-coupling of phenols with C2/C3-substituted benzothiophene S-oxides
He, Zhen,Biremond, Tony,Perry, Gregory J.P.,Procter, David J.
supporting information, (2020/06/17)
C2 and C3 substituted benzothiophenes are common structures in medicinal and materials chemistry. The cross-coupling of phenols with benzothiophenes is a useful route towards these important molecules. In this report we reveal an efficient C–H/C–H-type cross-coupling of benzothiophenes, activated as their S-oxides, with phenols to give C2/C3 arylated benzothiophenes. Whereas previous reports describe cross-coupling at the ortho-position between phenols and sulfoxides, this procedure allows para-functionalization of phenols that typically have their ortho positions blocked.
Synthesis of C2 Substituted Benzothiophenes via an Interrupted Pummerer/[3,3]-Sigmatropic/1,2-Migration Cascade of Benzothiophene S-Oxides
He, Zhen,Shrives, Harry J.,Fernández-Salas, José A.,Abengózar, Alberto,Neufeld, Jessica,Yang, Kevin,Pulis, Alexander P.,Procter, David J.
supporting information, p. 5759 - 5764 (2018/04/10)
Functionalized benzothiophenes are important scaffolds found in molecules with wide ranging biological activity and in organic materials. We describe an efficient, metal-free synthesis of C2 arylated, allylated, and propargylated benzothiophenes. The reaction utilizes synthetically unexplored yet readily accessible benzothiophene S-oxides and phenols, allyl-, or propargyl silanes in a unique cascade sequence. An interrupted Pummerer reaction between benzothiophene S-oxides and the coupling partners yields sulfonium salts that lack aromaticity and therefore allow facile [3,3]-sigmatropic rearrangement. The subsequently generated benzothiophenium salts undergo a previously unexplored 1,2-migration to access C2 functionalized benzothiophenes.
Benzothiophene S-Oxides and Related Compounds from the Reactions of Arylalkynes and Antimony Pentafluoride in Sulfur Dioxide
Fan, Ru-Lin,Dickstein, Jerome I.,Miller, Sidney I.
, p. 2466 - 2469 (2007/10/02)
When treated with antimony pentafluoride and benzene in liquid sulfur dioxide, certain alkynes yield 2-X-3-phenylbenzothiophene S-oxides (X = Ph, Cl, Br) or 1,1-diphenyl-2-X-vinylsulfinic acids (X = H, Br).Though limited, this is a facile route to both types of compounds.
