A novel metal-free synthesis of 3,3-disubstituted benzofuran-2-(3H)-ones through reacting α-aryl-α-diazoacetates with triarylboranes is presented. Initially, triarylboranes were successfully investigated in α-arylations of α-diazoacetates, however in the presence of a heteroatom in the ortho position, the boron enolate intermediate undergoes an intramolecular rearrangement to form a quaternary center. The intermediate cyclizes to afford valuable 3,3-disubstituted benzofuranones in good yields.
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http://dx.doi.org/10.1002/anie.201902985 | DOI Listing |
Org Biomol Chem
November 2024
Department of Chemistry, Savitribai Phule Pune University (Formerly University of Pune), Ganeshkhind, Pune-411007, India.
Under mild and metal-free reaction conditions, a facile one-pot synthesis of oxygen- and nitrogen-containing benzoheterocycles has been achieved through [4 + 1] annulation of -quinone methides, followed by an oxidation/elimination sequence, efficiently synthesizing functionalized 2,3-dihydrobenzofuran, benzofuran-2(3)-one, and indole derivatives in moderate to good yields (up to 72%). A novel functional group tolerant oxidative Nef reaction utilizes DDQ without a base.
View Article and Find Full Text PDFOrg Lett
October 2024
School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China.
An efficient palladium-catalyzed isomerization/hydrocarbonylation of electron-deficient alkenes was developed, affording a variety of benzofuran-2(3)-ones, dihydrofuran-2(3)-ones, indolin-2-ones, and isochroman-3-ones in high yields. The reaction exhibits excellent regioselectivity, high atom economy, and a broad range of substrates. The late-stage modification of bioactive molecules and scaled-up reaction demonstrated the practicability of this methodology.
View Article and Find Full Text PDFRSC Adv
December 2022
State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University Changsha 410082 P. R. China
We have developed a transition-metal free protocol for efficient cross-dehydrogenative coupling of 3-aryl benzofuran-2(3)-ones and toluenes/phenols using DTBP as an oxidant. A diverse range of 3-aryl benzofuran-2(3)-ones, toluenes, and phenols undergo C-H bond cleavage to generate all-carbon quaternary centers in good yields, making this protocol useful for the synthesis of complex molecules. A gram scale experiment was performed in good yield.
View Article and Find Full Text PDFAcc Chem Res
September 2022
Asymmetric organocatalysis has been considered to be an efficient and reliable strategy for the stereoselective preparation of optically active chemicals. In particular, chiral tertiary amines as Lewis base organocatalysts bearing core structures including quinuclidine, dimethylaminopyridine (DMAP), -methylimidazole (NMI), amidine, etc. have provided new and powerful tools for various chemical transformations.
View Article and Find Full Text PDFJ Org Chem
May 2022
State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China.
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