Fused-Ring Formation by an Intramolecular “Cut-and-Sew” Reaction between Cyclobutanones and Alkynes
作者:Lin Deng、Likun Jin、Guangbin Dong
DOI:10.1002/anie.201712487
日期:2018.3.1
alkynes to construct cyclohexenone‐fused rings is described herein. The challenge arises from the need for selective coupling at the more sterically hindered proximal position, and can be addressed by using an electron‐rich, but less bulky, phosphine ligand. The control experiment and 13C‐labelling study suggest that the reaction may start with cleavage of the less hindered distal C−C bond of cyclobutanones
Bromotrimethylsilane (TMSBr)-promoted intramolecular cyclization of (o-arylethynyl)benzylethers to form 1H-isochromenes at room temperature is reported. Further studies indicated that vinyl carbocations are the reaction intermediates which are stabilized by the conjugated aryl groups. Thus, O-addition of benzylethers/tetrahydropyrans to alkynes was achieved under metal-free, acidic conditions. These
报道了溴代三甲基硅烷 (TMSBr) 促进的 ( o -arylethynyl) 苄基醚在室温下分子内环化形成 1 H-异色烯。进一步的研究表明,乙烯基碳阳离子是由共轭芳基稳定的反应中间体。因此,在无金属、酸性条件下实现了苄基醚/四氢吡喃与炔烃的O-加成。这些反应条件与炔基普林斯反应相容;因此,使用一锅法直接由炔基苯甲醛和炔醇生产1 H-异色烯。
Studies on tellurium-containing heterocycles. Part 18.1 Preparation and structure of 2-benzotelluropyrylium salts and 2-benzoselenopyrylium salts
The regioselective and stereospecific intramolecular ring closure reactions of o-ethynylbenzyl tellurols 5A and o-ethynylbenzyl selenols 5B, which were readily generated by the reaction of the o-ethynylbenzyl bromides 4 with sodium hydrogen telluride (NaHTe) or sodium hydrogen selenide (NaHSe), produced the isotellurochromenes 6A and isoselenochromenes 6B together with (Z)-1-methylidene-2-telluraindans
Potassium <i>tert</i>-Butoxide-Catalyzed Synthesis of Benzofuroazepines via Cyclization of (2-Alkynylbenzyl)oxy Nitriles
作者:Rafaela Gai、Davi F. Back、Gilson Zeni
DOI:10.1021/acs.joc.5b01884
日期:2015.10.16
Herein, we report that potassium tert-butoxide-catalyzed intramolecular anioniccyclization of (2-alkynylbenzyl)oxy nitriles has been developed for the preparation of substituted benzofuroazepines. The effects of solvent, base, temperature, reaction time, and amount of base on the efficiency of cyclization reaction was investigated. The results led us to conclude that the reactions can be carried out
Synthesis of N 1 -substituted analogues of (2 R ,4 R )-4-amino-pyrrolidine-2,4-dicarboxylic acid as agonists, partial agonists, and antagonists of group II metabotropic glutamate receptors
作者:Jayanta Kumar Mukhopadhyaya、Alan P. Kozikowski、Ewa Grajkowska、Sergey Pshenichkin、Jarda T. Wroblewski
DOI:10.1016/s0960-894x(01)00329-8
日期:2001.7
The chemical synthesis of a series of N(1)-substituted derivatives of (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylic acid [(2R,4R)-APDC] as constrained analogues of gamma-substituted glutamic acids is described. Appropriate substitution of the N(1)-position results in agonist, partial agonist, or antagonist activity at mGluR2, mGluR3, and/or mGluR6.