16766-63-5Relevant articles and documents
Electrochemically Enabled, Nickel-Catalyzed Dehydroxylative Cross-Coupling of Alcohols with Aryl Halides
Li, Zijian,Sun, Wenxuan,Wang, Xianxu,Li, Luyang,Zhang, Yong,Li, Chao
supporting information, p. 3536 - 3543 (2021/03/08)
As alcohols are ubiquitous throughout chemical science, this functional group represents a highly attractive starting material for forging new C-C bonds. Here, we demonstrate that the combination of anodic preparation of the alkoxy triphenylphosphonium ion and nickel-catalyzed cathodic reductive cross-coupling provides an efficient method to construct C(sp2)-C(sp3) bonds, in which free alcohols and aryl bromides - both readily available chemicals - can be directly used as coupling partners. This nickel-catalyzed paired electrolysis reaction features a broad substrate scope bearing a wide gamut of functionalities, which was illustrated by the late-stage arylation of several structurally complex natural products and pharmaceuticals.
Hydrogen-Bonding Catalyzed Ring-Closing C?O/C?O Metathesis of Aliphatic Ethers over Ionic Liquid under Metal-Free Conditions
Wang, Huan,Zhao, Yanfei,Zhang, Fengtao,Wu, Yunyan,Li, Ruipeng,Xiang, Junfeng,Wang, Zhenpeng,Han, Buxing,Liu, Zhimin
supporting information, p. 11850 - 11855 (2020/05/16)
O-heterocycles have wide applications, and their efficient and green synthesis is very interesting. Herein, we report hydrogen-bonding catalyzed ring-closing metathesis of aliphatic ethers to O-heterocycles over ionic liquid (IL) catalyst under metal- and solvent-free conditions. The IL 1-butylsulfonate-3-methylimidazolium trifluoromethanesulfonate ([SO3H-BMIm][OTf]) is discovered to show outstanding performance, better than the reported catalysts. An interface effect plays an important role in mediating the reaction rate due to the immiscibility between the products and the IL catalyst, and the products can be spontaneously separated. NMR analysis and DFT calculation suggest that a pair of cation and anion of [SO3H-BMIm][OTf] could form three strong H-bonds with an ether molecule, which catalyze the ether transformation via a cyclic oxonium intermediate. A series of O-heterocycles including tetrahydrofurans, tetrahydropyrans, morpholines and dioxane can be obtained from their corresponding ethers in excellent yields (e.g., >99 %). This work opens an efficient and metal-free way to produce O-heterocycles from aliphatic ethers.
Iron-Catalyzed Ring-Closing C?O/C?O Metathesis of Aliphatic Ethers
Biberger, Tobias,Makai, Szabolcs,Lian, Zhong,Morandi, Bill
supporting information, p. 6940 - 6944 (2018/05/14)
Among all metathesis reactions known to date in organic chemistry, the metathesis of multiple bonds such as alkenes and alkynes has evolved into one of the most powerful methods to construct molecular complexity. In contrast, metathesis reactions involving single bonds are scarce and far less developed, particularly in the context of synthetically valuable ring-closing reactions. Herein, we report an iron-catalyzed ring-closing metathesis of aliphatic ethers for the synthesis of substituted tetrahydropyrans and tetrahydrofurans, as well as morpholines and polycyclic ethers. This transformation is enabled by a simple iron catalyst and likely proceeds via cyclic oxonium intermediates.
Cyclic ether synthesis from diols using trimethyl phosphate
Asai, Shota,Kato, Maho,Monguchi, Yasunari,Sajiki, Hironao,Sawama, Yoshinari
supporting information, p. 4787 - 4790 (2017/07/06)
Cyclic ethers have been effectively synthesized via the intramolecular cyclization of diols using trimethyl phosphate and NaH. The present cyclization could proceed at room temperature to produce 5-7 membered cyclic ethers in good to excellent yields. Substrates possessing a chiral secondary hydroxy group were transformed into the corresponding chiral cyclic ethers along with the retention of their stereochemistries.
Asymmetric hydrogenation of furans and benzofurans with iridium-pyridine-phosphinite catalysts
Pauli, Larissa,Tannert, Re,Scheil, Robin,Pfaltz, Andreas
, p. 1482 - 1487 (2015/01/30)
Enantioselective hydrogenation of furans and benzofurans remains a challenging task. We report the hydrogenation of 2- and 3-substituted furans by using iridium catalysts that bear bicyclic pyridine-phosphinite ligands. Excellent enantioselectivities and high conversions were obtained for monosubstituted furans with a 3-alkyl or 3-aryl group. Furans substituted at the 2-position and 2,4-disubstituted furans proved to be more difficult substrates. The best results (80-97% conversion, 65-82% enantiomeric excess) were obtained with monosubstituted 2-alkylfurans and 2-[4-(trifluoromethyl)phenyl]furan. Benzofurans with an alkyl substituent at the 2- or 3-position also gave high conversions and enantioselectivity, whereas 2-aryl derivatives showed essentially no reactivity. The asymmetric hydrogenation of a 3-methylbenzofuran derivative was used as a key step in the formal total synthesis of the cytotoxic naphthoquinone natural product (-)-thespesone.
Synthesis of 3-substituted tetrahydrofuran and 4-substituted tetrahydropyran derivatives by cyclization of dicarboxylic acids with InBr 3/TMDS
Pehlivan, Leyla,Metay, Estelle,Delbrayelle, Dominique,Mignani, Gerard,Lemaire, Marc
supporting information; experimental part, p. 4689 - 4693 (2012/09/22)
An efficient reduction followed by cyclization of diacid compounds with the InBr3/TMDS system is reported. This system allows the formation of five- and six-membered ring ethers substituted in the 3- or 4-position. Copyright
Chiral hetero- and carbocyclic compounds from the asymmetric hydrogenation of cyclic alkenes
Verendel, J. Johan,Li, Jia-Qi,Quan, Xu,Peters, Byron,Zhou, Taigang,Gautun, Odd R.,Govender, Thavendran,Andersson, Pher G.
supporting information; experimental part, p. 6507 - 6513 (2012/06/29)
Several types of chiral hetero- and carbocyclic compounds have been synthesized by using the asymmetric hydrogenation of cyclic alkenes. N,P-Ligated iridium catalysts reduced six-membered cyclic alkenes with various substituents and heterofunctionality in good to excellent enantioselectivity, whereas the reduction of five-membered cyclic alkenes was generally less selective, giving modest enantiomeric excesses. The stereoselectivity of the hydrogenation depended more strongly on the substrate structure for the five- rather than the six-membered cyclic alkenes. The major enantiomer formed in the reduction of six-membered alkenes could be predicted from a selectivity model and isomeric alkenes had complementary enantioselectivity, giving opposite optical isomers upon hydrogenation. The utility of the reaction was demonstrated by using it as a key step in the preparation of chiral 1,3-cis-cyclohexane carboxylates. Copyright
A facile synthesis of 5,6-dihydro-4H-pyrrolo[3,4-d]thiazole and other pyrrolidine-fused aromatic ring systems via one-step cyclization from diols
Yoshikawa, Kenji,Nagata, Tsutomu,Yoshino, Toshiharu,Nakamoto, Yumi,Haginoya, Noriyasu,Muto, Ryo,Mochizuki, Akiyoshi,Kanno, Hideyuki,Ohta, Toshiharu
experimental part, p. 1711 - 1720 (2012/09/07)
A facile synthetic method of 5,6-dihydro-4H-pyrrolo[3,4-d]thiazole, which is a subunit of a potent factor Xa (fXa) inhibitor was developed. This new approach employs one-step cyclization from a diol and can be applied to the syntheses of other pyrrolidine-fused aromatic ring sytems.
Gold-catalyzed substitution reaction with ortho-alkynylbenzoic acid alkyl ester as an efficient alkylating agent
Aikawa, Haruo,Tago, Sakie,Umetsu, Kazuteru,Haginiwa, Naomichi,Asao, Naoki
experimental part, p. 1774 - 1784 (2009/06/20)
ortho-Alkynylbenzoic acid alkyl esters behave as alkylating agents in combination with gold catalysts. The reaction with alcohols occurs smoothly in the presence of catalytic amounts of Ph3PAuCl and AgOTf under mild conditions to produce the corresponding ether products in high yields. The protocol is also useful for Friedel-Crafts alkylation and N-alkylation of sulfonamides. The reaction likely proceeds through the gold-induced in situ construction of leaving groups and subsequent nucleophilic attack of nucleophiles, such as alcohols, aromatic compounds, and sulfonamides.
