Readily available and inexpensive Earth-abundant alkali metal species are used as efficient catalysts for the transesterification of aryl or heteroaryl esters with phenols which is a challenging and underdeveloped transformation. The simple conditions and the use of heterogeneous alkali metal catalyst make this protocol very environmentally friendly and practical. This reaction fills in the missing part in transesterification reaction of phenols and provides an efficient approach to aryl esters, which are widely used in the synthetic and pharmaceutical industry.
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http://dx.doi.org/10.1039/c8ra04984j | DOI Listing |
J Org Chem
January 2025
Key Laboratory of Drug-Targeting and Drug Delivery System of Education Ministry, Department of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, No. 17, Third Section, South Renmin Road, Chengdu 610041, P. R. China.
A photoredox-promoted cascade glycosylation/cyclization reaction of 2-isocyanobiaryls and glycosyl NHP esters was established for the synthesis of nonclassical heteroaryl C-glycosides. This methodology is characterized by an exceedingly simple reaction system, high diastereoselectivity, and good functional group tolerance. In contrast to traditional strategies, this innovative approach circumvents the need for high temperature, transition metal, and photocatalyst, offering an environmentally friendly and efficient protocol.
View Article and Find Full Text PDFChemistry
December 2024
Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023, Dalian, Liaoning, China.
Herein we report a "carbonylative migration" strategy for the acylation-esterification type double functionalization of unactivated alkenes using alkyloxalkyl chlorides and CO as the reagents. The transformation is proceeded by the alkoxycarbonyl radical addition to unactivated alkenes, followed by the insertion of carbon monoxide to induce intramolecular migration of heteroaryl groups, which is different from the traditional reaction modes. The reaction conditions were mild and well tolerated with varieties of functional groups.
View Article and Find Full Text PDFOrg Lett
November 2024
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
-(Diphenylphosphinyl)hydroxylamine (DPPH) is a general reagent for the conversion of (hetero)aryl boronic acids and esters to primary anilines. The transformation proceeds rapidly at rt and exhibits a broad substrate scope and exceptional functional-group tolerance. In terms of rate, the reaction is relatively insensitive to the electronic properties of the substrate, in contrast to similar reactions using electrophilic amination reagents such as hydroxylamine--sulfonic acid.
View Article and Find Full Text PDFJ Org Chem
December 2024
Graduate School of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu Shiga 525-8577, Japan.
Herein, we report the development of metal-free one/two-pot procedures for the synthesis of benzo[]isoxazol-3(1)-one (benzisoxazolone) heterocycles by designing diaryliodonium salts featuring -ester or nitrile functional groups. These react smoothly with protected hydroxylamines under mild conditions to produce -arylhydroxylamine intermediates, which readily cyclize to give benzisoxazolone derivatives under acidic conditions. This metal-free process maintains the weak N-O bond, tolerates a wide range of diaryliodonium salts and protected hydroxylamines with diverse functional/protecting groups, thereby overcoming the challenges associated with previous transformations.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
Department of Chemistry, Indian Institute of Technology Jammu, Jagti, NH-44, Nagrota Bypass, Jammu J&K, 181221, India.
The development of Michael addition reactions to conjugated cyclopropenes is a challenge in organic synthesis due to the fleeting and reactive nature of such strained Michael acceptor systems. Herein, the development of a photochemical approach towards such conjugated cyclopropenes is reported that serves as a strategic entry point to densely functionalized cyclopropanes in a diastereoselective fashion. The process involves the light-mediated generation of transient cyclopropenyl α,β-unsaturated esters from vinyl diazo esters, followed by an organic base catalyzed nucleophilic addition of N-heterocycles to directly access β-N-heterocyclic cyclopropanoic esters.
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