- Gold-Catalyzed Amide/Carbamate-Linked N, O-Acetal Formation with Bulky Amides and Alcohols
-
A gold-catalyzed N,O-acetal formation was established to construct an amide/carbamate-linked N,O-acetal substructure with bulky alcohols. The acyliminium cation species generated from o-alkynylbenzoic acid ester in the presence of a gold catalyst is highly reactive and underwent nucleophilic attack of various bulky alcohols and phenols at room temperature under neutral conditions, leading to the corresponding N,O-acetals in yields of 34-89% with good functional group tolerance.
- Ohsawa, Kosuke,Ochiai, Shota,Kubota, Junya,Doi, Takayuki
-
p. 1281 - 1291
(2021/01/14)
-
- Copper-Catalyzed Modular Access to N-Fused Polycyclic Indoles and 5-Aroyl-pyrrol-2-ones via Intramolecular N—H/C—H Annulation with Alkynes: Scope and Mechanism Probes
-
Copper-catalyzed intramolecular N—H/C—H annulation with alkynes has been developed. A variety of densely functionalized heterocycles, such as pyrrolo[1,2-a]indoles, indolo[1,2-c]quinazolin-2-ones, oxazolo[3,4-a]indoles, and imidazo[1,5-a]indoles, were synthesized in an atom- and step-economical manner, owing to the high modularized feature of aniline moiety, the linker moiety, as well as the alkyne moiety. By simply changing the oxidant from di-tert-butyl peroxide (DTBP) to 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), the reaction could readily be transformed to the aminooxygenation pathway, which grabs one oxygen atom from the TEMPO to generate 5-aroyl-pyrrol-2-ones. Mechanistic experiments indicate that vinyl radical is involved in this reaction and an amidyl-radical-initiated radical cascade might be responsible for this transformation.
- Liu, Yan-Hua,Song, Hong,Zhang, Chi,Liu, Yue-Jin,Shi, Bing-Feng
-
supporting information
p. 1545 - 1552
(2020/09/09)
-
- Continuous Electrochemical Synthesis of Iso-Coumarin Derivatives from o-(1-Alkynyl) Benzoates under Metal- and Oxidant-Free
-
A non-oxidant and metal-free strategy for synthesizing iso-coumarin by using a continuous electrochemical microreactor to initiate an oxidative cyclization reaction of o-(1-alkynyl) benzoate and radicals. This efficient and clean continuous electrosynthesis method not only avoids the complicated gas protection operation and production of by-products in the batch processes, but also help to overcome the difficulty that batch metal catalysis and electrocatalysis are difficult to scale up, and has the potential for pilot-scale experiment.
- Lin, Xinxin,Fang, Zheng,Zeng, Cuilian,Zhu, Chenlong,Pang, Xinyan,Liu, Chengkou,He, Wei,Duan, Jindian,Qin, Ning,Guo, Kai
-
supporting information
p. 13738 - 13742
(2020/10/02)
-
- Borylative Heterocyclization without Air-Free Techniques
-
In contrast to previously reported borylative heterocyclization methods, a reaction here proceeds without air-free techniques to access synthetically useful borylated thiophenes, benzothiophenes, and isocoumarins. A comparison of stability/decomposition rates in air of several catecholboronic ester (Bcat) compounds derived from different heterocycle cores showed a strong dependence on the heterocycle structure. Lessons learned from this comparison were then harnessed for the development of borylative heterocyclization reactions under ambient-atmosphere conditions and with wet solvent. In contrast to literature reports suggesting general moisture sensitivity, a subset of Bcat products resulting from this technique were chromatography-stable and directly isolable, obviating the requirement for an extra synthetic transformation into more stable boron species, such as pinacolboronic esters (Bpin), for isolation. The isolated Bcat products were amenable to various downstream functionalization reactions, including reactions that were not accessible with their better-known Bpin counterparts, showing the complementarity of Bcat reaction partners and expanding their known chemistry. These results suggest the value of conceptual revisitation of substitution and solvent influence on stability and isolability of organo-Bcat compound classes and lay the groundwork for development of additional practical borylative methods in air.
- Blum, Suzanne A.,Gao, Chao,Nakao, Shuichi
-
supporting information
p. 10350 - 10368
(2020/09/23)
-
- Gold(i)-catalyzed Nicholas reaction with aromatic molecules utilizing a bifunctional propargyl dicobalt hexacarbonyl complex
-
A benchtop-stable reagent for the catalytic Nicholas reaction was developed. By combining a propargyl dicobalt hexacarbonyl cluster with an ortho-alkynylbenzoate unit and a fluorous tag, introduction of a propargyl hexacarbonyl complex on various aromatic compounds having acid- or base-sensitive functional groups becomes possible by using a gold(i) catalyst. In addition, the presence of a fluorous tag facilitates convenient separation of the target products from byproducts.
- Okamura, Toshitaka,Fujiki, Shogo,Iwabuchi, Yoshiharu,Kanoh, Naoki
-
supporting information
p. 8522 - 8526
(2019/10/02)
-
- Gold-catalyzed Rapid Construction of Nitrogen-containing Heterocyclic Compound Library with Scaffold Diversity and Molecular Complexity
-
1,3-unsubstituted 2-(1H-indol-2-yl)ethanamines were employed for the first time to react with alkynoic acids (AAs) to achieve gold-catalyzed highly selective cascade reactions to furnish novel indole-fused skeletons. Furthermore, with this powerful gold catalytic system, a library of indole/pyrrole/thiophene/benzene/naphthalene/pyridine-based nitrogen-containing heterocyclic compounds (NCHCs) with scaffold diversity and molecular complexity was constructed rapidly using various amine nucleophiles (ANs) and diverse AAs as the building blocks. This general protocol features excellent selectivity, extraordinarily broad substrate scope, readily available inputs, good to high yields, high bond-forming efficiency, and step economy, thus providing a facile and efficient access to a variety of valuable nitrogen-containing heterocycles.
- Qiao, Jin,Jia, Xiuwen,Li, Pinyi,Liu, Xiaoyan,Zhao, Jingwei,Zhou, Yu,Wang, Jiang,Liu, Hong,Zhao, Fei
-
-
- Metal-Free Synthesis of 4-Chloroisocoumarins by TMSCl-Catalyzed NCS-Induced Chlorinative Annulation of 2-Alkynylaryloate Esters
-
4-Chloroisocoumarins can be conveniently prepared from 2-alkynylaryloate esters via the activation of alkynes by electrophilic chlorine, generated in situ from N-chlorosuccinimide (NCS) in the presence of 10 mol % trimethylsilyl chloride (TMSCl), which leads to 6-endo-dig-selective chlorinative annulation to give the desired products in moderate to quantitative yields. The procedure employs readily available reagents and can be conveniently carried out on a wide scope of substrates under mild conditions (0 °C to rt). Furthermore, the reaction is scalable for gram-scale preparation of 4-chloroisocoumarins. Additionally, 4-bromo- and 4-iodoisocoumarins can be prepared in moderate to good yields by replacing NCS with N-bromosuccinimide (NBS) and N-iodosuccinimide (NIS), respectively.
- Norseeda, Krissada,Chaisan, Nattawadee,Thongsornkleeb, Charnsak,Tummatorn, Jumreang,Ruchirawat, Somsak
-
p. 16222 - 16236
(2019/12/25)
-
- Gold promoted arylative cyclization of alkynoic acids with arenediazonium salts
-
Alkynoic acids derived from salicylic acid and analogues undergo arylative cyclization with arenediazonium salts promoted by gold in the absence of external ligands. The reaction is thermally induced and proceeds even in the absence of light. A difference in regioselectivity has been found compared with that observed in the cycloisomerization process of the same type of compounds.
- Carrillo-Arcos, Ulises A.,Porcel, Susana
-
supporting information
p. 1837 - 1842
(2018/03/23)
-
- Divergent Syntheses of (Z)-3-Alkylideneisobenzofuran-1(3 H)-ones and 1 H-Isochromen-1-ones by Copper-Catalyzed Cycloisomerization of 2-Alkynylbenzoic Acids in Ionic Liquids
-
The cycloisomerization of readily available 2-alkynylbenzoic acids 1 in ionic liquids (ILs) as recyclable reaction media has been studied under the catalytic action of CuCl2. With substrates bearing an aryl group on the triple bond, a mixture o
- Mancuso, Raffaella,Pomelli, Christian S.,Chiappetta, Piera,Gioia, Katia F.,Maner, Asif,Marino, Nadia,Veltri, Lucia,Chiappe, Cinzia,Gabriele, Bartolo
-
p. 6673 - 6680
(2018/06/01)
-
- Divergent syntheses of iodinated isobenzofuranones and isochromenones by iodolactonization of 2-alkynylbenzoic acids in ionic liquids
-
The regiochemical outcome of the iodolactonization of 2-alkynylbenzoic acids, carried out at 100 °C in ionic liquids (ILs) as unconventional solvents and with molecular iodine as the iodine source, in the absence of external bases, was found to be strongl
- Mancuso, Raffaella,Pomelli, Christian C.,Malafronte, Francesco,Maner, Asif,Marino, Nadia,Chiappe, Cinzia,Gabriele, Bartolo
-
supporting information
p. 4831 - 4841
(2017/07/10)
-
- Hydroiodination-Triggered Cascade Reaction with I2/PPh3/H2O: Metal-Free Access to 3-Substituted Phthalides from 2-Alkynylbenzoates
-
Phthalide is an important scaffold found in several biologically active compounds. Therefore, effective methods for the synthesis of phthalides are strongly desired. Herein, we describe the metal-free synthesis of 3-substituted phthalides by the reductive hydroiodination of 2-alkynylbenzoates through an I2/PPh3/H2O-triggered cascade reaction. A variety of 3-substituted phthalides were synthesized in excellent yields by a one-pot reaction involving four processes: desilylation, hydroiodination, cyclization, and reduction.
- Kawaguchi, Shin-Ichi,Nakamura, Kentaro,Yamaguchi, Kotaro,Sato, Yuki,Gonda, Yuhei,Nishioka, Masaaki,Sonoda, Motohiro,Nomoto, Akihiro,Ogawa, Akiya
-
supporting information
p. 5343 - 5346
(2017/09/06)
-
- Catalyst-Free Synthesis of Borylated Lactones from Esters via Electrophilic Oxyboration
-
A catalyst-free oxyboration reaction of alkynes is developed. The resulting borylated isocoumarins and 2-pyrones are isolated as boronic acids, pinacolboronate esters, or potassium organotrifluoroborate salts, providing a variety of bench-stable organobor
- Faizi, Darius J.,Issaian, Adena,Davis, Ashlee J.,Blum, Suzanne A.
-
supporting information
p. 2126 - 2129
(2016/03/05)
-
- Synthesis of isocoumarins: Rhenium complex-catalyzed cyclization of 2-ethynylbenzoic acids
-
When 2-ethynylbenzoic acids were treated with a catalytic amount of a rhenium complex, such as ReCl(CO)5, 6-endo cyclization of 2-ethynylbenzoic acids proceeded with a high selectivity to give the corresponding isocoumarins in moderate to good yields.
- Umeda, Rui,Yoshikawa, Shunya,Yamashita, Kouji,Nishiyama, Yutaka
-
p. 2172 - 2179
(2015/12/12)
-
- Palladium(II)-catalyzed tandem annulation reaction of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins
-
A palladium(II)-catalyzed highly regioselective tandem reactions of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins was developed. It is a convenient, mild and environmentally benign reaction with moderate to high yield. The
- Wang, Huan,Han, Xiuling,Lu, Xiyan
-
p. 8626 - 8631
(2013/09/12)
-
- On homogeneous gold/palladium catalytic systems
-
Two substrates containing an aryl iodide and an allenoate ester were prepared and the goldinduced cycloisomerisation to vinylgold(I) species and their proto-deauration as well as the intramolecular palladium-catalysed cross-coupling reactions were investigated. Switching to catalytic amounts of gold and palladium and stoichiometric amounts of silver did indeed furnish the product of a cycloisomerisation/ intramolecular cross-coupling. Control experiments revealed that silver cannot substitute for gold or palladium in these reactions, but a different palladium catalyst in a different oxidation state also afforded the cycloisomerisation/intramolecular crosscoupling products in only slightly reduced yields. By ICP analysis the palladium was shown to contain gold only at the sub-ppm level. This shows how carefully results obtained with such systems have to be interpreted. Then a series of allylic and benzylic o-alkynylbenzoates were investigated in gold-and palladium-catalysed reactions. For esters of benzyl alcohol and cinnamyl alcohol no palladium co-catalyst was needed for the conversion. All reagents were thoroughly checked for palladium traces by ICP analysis in order to thoroughly exclude a gold/palladium cocatalysis. Optimisation of the gold complex, counter ion and solvent showed that gold(I) isonitrile precatalysts and silver triflate as activator in dioxane are suitable to convert a number of substrates with aryl, alkyl and even cyclopropyl substituents. Crossover experiments proved an intermolecular allyl transfer.
- Hashmi, A. Stephen K.,Lothschuetz, Christian,Doepp, Rene,Ackermann, Martin,De Buck Becker, Janosc,Rudolph, Matthias,Scholz, Christian,Rominger, Frank
-
supporting information; experimental part
p. 133 - 147
(2012/04/10)
-
- Gold(I)-Catalyzed glycosylation with glycosyl ortho-alkynylbenzoates as donors: General scope and application in the synthesis of a cyclic triterpene saponin
-
Glycosyl ortho-alkynylbenzoates have emerged as a new generation of donors for glycosidation under the catalysis of gold(I) complexes such as Ph 3PAuOTf and Ph3PAuNTf2 (Tf= trifluoromethanesulfonate). A wide variety of these donors, including 2-deoxy sugar and sialyl donors, are easily prepared and shelf stable. The glycosidic coupling yields with alcohols are gener-ally excellent; even direct coupling with the poorly nucleophilic amides gives satisfactory yields. Moreover, excellent α-selective glycosylation with a 2-deoxy sugar donor and β-selective sialylation have been realized. Application of the present glycosylation protocol in the efficient synthesis of a cyclic triterpene tetrasaccharide have further demonstrated the versatility and efficacy of this new method, in that a novel chemoselective glycosylation of the carboxylic acid and a new one-pot sequential glycosylation sequence have been implemented.
- Li, Yao,Yang, Xiaoyu,Liu, Yunpeng,Zhu, Cunsheng,Yang, You,Yu, Biao
-
experimental part
p. 1871 - 1882
(2010/06/20)
-
- Tuning selectivity of anionic cyclizations: Competition between 5-exo and 6-endo-dig closures of hydrazides of o-acetylenyl benzoic acids and based-catalyzed fragmentation/recyclization of the initial 5-exo-dig products
-
(Chemical Equation Presented) Depending on the reaction conditions and the nature of substituents at the triple bond, anionic cyclizations of hydrazides of o-acetylenyl benzoic acids can be selectively directed along three alternative paths, each of which
- Vasilevsky, Sergey F.,Mikhailovskaya, Tat'yana F.,Mamatyuk, Victor I.,Salnikov, Georgy E.,Bogdanchikov, Georgy A.,Manoharan, Mariappan,Alabugin, Igor V.
-
supporting information; experimental part
p. 8106 - 8117
(2010/03/04)
-
- Synthesis of 3-alkyl naphthalenes as novel estrogen receptor ligands
-
A series of estrogen receptor ligands based on a 3-alkyl naphthalene scaffold was synthesized using an intramolecular enolate-alkyne cycloaromatization as the key step. Several of these compounds bearing a C6-OH group were shown to be high affinity ligand
- Fang, Jing,Akwabi-Ameyaw, Adwoa,Britton, Jonathan E.,Katamreddy, Subba R.,Navas III, Frank,Miller, Aaron B.,Williams, Shawn P.,Gray, David W.,Orband-Miller, Lisa A.,Shearin, Jean,Heyer, Dennis
-
scheme or table
p. 5075 - 5077
(2009/05/07)
-
- CHEMICAL COMPOUNDS
-
The present invention relates to novel compounds with a variety of therapeutic uses, more particularly novel naphthalene compounds that are particularly useful for selective estrogen receptor modulation.
- -
-
Page/Page column 91
(2010/02/15)
-
- Versatile synthesis of (Z)-1-alkylidene-1,3-dihydroisobenzofurans and 1H-isochromenes by palladium-catalyzed cycloisomerization of 2-alkynylbenzyl alcohols
-
An easy synthesis of (Z)-1-alkylidene-1,3-dihydroisobenzofurans and 1H-isochromenes by palladium-catalyzed cycloisomerization of readily available 2-alkynylbenzyl alcohols under neutral conditions is reported. Reactions were carried out at 70-100°C in the
- Gabriele, Bartolo,Salerno, Giuseppe,Fazio, Alessia,Pittelli, Rosina
-
p. 6251 - 6259
(2007/10/03)
-
- On the diverse outcomes of base-induced cyclisations of 2-alkynylphenylhydroxamic acids
-
Base-induced cyclisations of 2-alkynylphenylhydroxamic acids occur by attack of nitrogen onto the alkyne group in either exo or endo fashions to give the corresponding isoindol-1(2H)-ones or 1(2H)-isoquinolinones depending upon the alkyne substituent.
- Knight, David W.,Lewis, Paul B.M.,Abdul Malik,Mshvidobadze, Elena V.,Vasilevsky, Sergei F.
-
p. 9187 - 9189
(2007/10/03)
-