863870-92-2Relevant academic research and scientific papers
Transition Metal-Free Synthesis of Halobenzo[b]furans from O-Aryl Carbamates via o-Lithiation Reactions
Feberero, Claudia,Renedo, Lorena,Sanz, Roberto,Sedano, Carlos,Suárez-Pantiga, Samuel,Virumbrales, Cintia
, (2022/01/24)
A straightforward and transition metal-free one-pot protocol to synthesize halobenzo[b]furans has been developed employing simple and easily available starting materials such as O-aryl carbamates and alkynylsulfones. The fine-tuning of the different steps involved was key to achieving a successful one-pot procedure. Initially, a directed ortho-lithiation process, which uses the carbamate as the directed metalation group, was crucial in providing access to O-2-alkynylaryl N,N-diethyl carbamates by a direct alkynylation of the o-lithiated carbamate, with arylsulfonylalkynes as electrophilic reagents. Cyclization of the generated o-alkynylaryl carbamates was successfully accomplished through a strategy involving in situ carbamate alkaline hydrolysis under conventional heating or microwave irradiation, coupled with a subsequent heterocyclization step delivering the desired benzo[b]furans. A wide variety of new halobenzo[b]furans has been synthesized and their utility has been demonstrated by their further transformation.
Strategy for Overcoming Full Reversibility of Intermolecular Radical Addition to Aldehydes: Tandem C-H and C-O Bonds Cleaving Cyclization of (Phenoxymethyl)arenes with Carbonyls to Benzofurans
Zheng, Hong-Xing,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
, p. 3310 - 3313 (2018/06/11)
An intermolecular addition of carbon radicals enabled by a cascade radical coupling strategy is developed. It includes an intermolecular alkyl radical addition to a carbonyl group followed by an intramolecular alkoxy radical addition to haloarenes and produces substituted benzofurans in high yields. The radical nature of this reaction is explored by radical trapping experiments and EPR analysis. The mechanism is investigated by KIE experiments and control experiments. This method could provide rapid and practical access to the key intermediate of TAM-16, a safe and potent antibacterial agent for treating tuberculosis, and, therefore, is of great importance for organic synthesis and the pharmaceutical industry.
Twofold unsymmetrical C-H functionalization of PyrDipSi-substituted arenes: A general method for the synthesis of substituted meta-halophenols
Sarkar, Dhruba,Melkonyan, Ferdinand S.,Gulevich, Anton V.,Gevorgyan, Vladimir
, p. 10800 - 10804 (2013/10/22)
And the world is your oyster Sequential halogenation/oxygenation reactions of 2-diisopropylsilylpyrimidine-substituted arenes provide a general and efficient synthesis of substituted meta-halophenols from simple aryl iodides (see scheme; Piv=pivaloyl). The products are poised to undergo diverse C-C, C-N, and C-O bond-forming reactions that enable the transformation of their framework and the introduction of valuable functionalities. Copyright
Efficient synthesis of benzofurans utilizing [3,3]-sigmatropic rearrangement triggered by N-trifluoroacetylation of oxime ethers: Short synthesis of natural 2-arylbenzofurans
Takeda, Norihiko,Miyata, Okiko,Naito, Takeaki
, p. 1491 - 1509 (2008/09/19)
A new synthetic method for the preparation of benzofurans has been developed. The key step of this method is the [3,3]-sigmatropic rearrangement of N-trifluoroacetyl-ene-hydroxylamines, which was triggered by acylation of oxime ethers. TFAA has been proved to be the best reagent to induce [3,3]-sigmatropic rearrangement for the synthesis of cyclic or acyclic dihydrobenzofurans. On the other hand, the TFAT-DMAP system is found to be the most effective for constructing various benzofurans. Synthetic utility of this reaction is demonstrated by the short synthesis of natural benzofurans without protection of the hydroxy group. The synthesis of Stemofuran A was accomplished via condensation of ketones with aryloxyamine and subsequent reaction with TFAT-DMAP in a four-step synthesis with 72% overall yield. Similarly, Eupomatenoid 6 and Coumestan were synthesized through the reaction of oxime ether with TFAT-DMAP. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
A new and efficient synthesis of 4-functionalized benzo[6]furans from 2,3-dihalophenols
Sanz, Roberto,Castroviejo, M. Pilar,Fernandez, Yolanda,Fananas, Francisco J.
, p. 6548 - 6551 (2007/10/03)
Tandem Sonogashira coupling/5-endo-dig cyclization reactions on 2,3-dihalophenols suppose a straightforward entry to 4-halobenzo[b]furans, which can be easily transformed into 4-functionalized benzo[b]furans, that are difficult to synthesize by other proc
