共查询到20条相似文献,搜索用时 31 毫秒
1.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(40):12460-12464
Highly selective divergent cycloaddition reactions of enoldiazo compounds and α‐diazocarboximides catalyzed by copper(I) or dirhodium(II) have been developed. With tetrakis(acetonitrile)copper(I) tetrafluoroborate as the catalyst epoxypyrrolo[1,2‐a]azepine derivatives were prepared in good yields and excellent diastereoselectivities through the first reported [3+3]‐cycloaddition of a carbonyl ylide. Use of Rh2(pfb)4 or Rh2(esp)2 directs the reactants to regioselective [3+2]‐cycloaddition generating cyclopenta[2,3]pyrrolo[2,1‐b]oxazoles with good yields and excellent diastereoselectivities. 相似文献
2.
Hiroshi Takikawa Arata Nishii Hiromu Takiguchi Hirotoshi Yagishita Masato Tanaka Keiichi Hirano Masanobu Uchiyama Ken Ohmori Keisuke Suzuki 《Angewandte Chemie (International ed. in English)》2020,59(30):12440-12444
An intramolecular benzyne–phenolate [4+2] cycloaddition is reported. Benzyne precursors, having vicinal halogen‐sulfonate functionalities, linked with a phenol(ate) by various tether groups undergo efficient intramolecular [4+2] cycloaddition by treatment with either Ph3MgLi or nBuLi for halogen–metal exchange to form various benzobarrelenes. 相似文献
3.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(49):15776-15780
A metal‐free [2+2] cycloaddition and 1,4‐addition sequence induced by S‐centered radicals has been achieved by treating benzene‐linked allene‐ynes with aryldiazonium tetrafluoroborates and DABCO‐bis(sulfur dioxide) in a one‐pot procedure. The reaction provides a greener and more practical access to functionalized cyclobuta[a]naphthalen‐4‐ols with valuable applications. More than 50 examples are demonstrated with excellent diastereoselectivity and chemical yields. The reaction pathway is proposed to proceed by the following steps:[2+2] cycloaddition, insertion of SO2, 1,4‐addition, diazotization, and tautomerization. 相似文献
4.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(6):1612-1616
We report herein the first enantioselective cycloaddition of vinyl oxetanes, the reaction of which with azadienes provided unprecedented access to ten‐membered heterocycles through a [6+4] cycloaddition. By using a commercially available chiral Pd‐SIPHOX catalyst, a wide range of benzofuran‐ as well as indole‐fused heterocycles could be accessed in excellent yield and enantioselectivity. A unique Lewis acid induced fragmentation of these ten‐membered heterocycles was also discovered. 相似文献
5.
Bowen Zhang Huw M. L. Davies 《Angewandte Chemie (International ed. in English)》2020,59(12):4937-4941
The reaction of 2‐siloxycyclo‐1,3‐dienes with E‐vinyldiazoacetates in the presence of the bulky chiral dirhodium tetracarboxylate catalyst, Rh2(R‐p‐PhTPCP)4 results in an enantioselective [4+2] cycloaddition, in which three new stereogenic centers are formed. The [4+2] cycloadducts are generated as single diastereomers with high enantiocontrol (95–98 % ee). When the diene contains an additional stereogenic center, effective kinetic resolution can be achieved. 相似文献
6.
Rhodium‐Catalyzed [3+2+2] and [2+2+2] Cycloadditions of Two Alkynes with Cyclopropylideneacetamides
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Tomoka Yoshida Yuki Tajima Masayuki Kobayashi Koji Masutomi Prof. Dr. Keiichi Noguchi Prof. Dr. Ken Tanaka 《Angewandte Chemie (International ed. in English)》2015,54(28):8241-8244
It has been established that a cationic rhodium(I)/H8‐binap complex catalyzes the [3+2+2] cycloaddition of 1,6‐diynes with cyclopropylideneacetamides to produce cycloheptadiene derivatives through cleavage of cyclopropane rings. In contrast, a cationic rhodium(I)/(S)‐binap complex catalyzes the enantioselective [2+2+2] cycloaddition of terminal alkynes, acetylenedicarboxylates, and cyclopropylideneacetamides to produce spiro‐cyclohexadiene derivatives which retain the cyclopropane rings. 相似文献
7.
Prof. Takahide Fukuyama Yuko Ohta Dr. Célia Brancour Kazusa Miyagawa Prof. Ilhyong Ryu Dr. Anne‐Lise Dhimane Prof. Louis Fensterbank Prof. Max Malacria 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(23):7243-7247
We have developed novel Rh‐catalyzed [n+1]‐type cycloadditions of 1,4‐enyne esters, which involve an acyloxy migration as a key step. The efficient preparation of functionalized resorcinols, including biaryl derivatives, from readily available 1,4‐enyne esters and CO was achieved by Rh‐catalyzed [5+1] cycloaddition accompanied by 1,2‐acyloxy migration. When enyne esters had an internal alkyne moiety, the reaction proceeded by a [4+1]‐type cycloaddition involving 1,3‐acyloxy migration, leading to cyclopentenones. 相似文献
8.
Benjamin W. Gung Prof. Dr. Derek T. Craft Lauren N. Bailey Kristin Kirschbaum Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(2):639-644
Macrocyclic propargyl acetates containing a furan ring were prepared by using a CrCl2‐promoted reaction. In the presence of either a AuI or AuIII catalyst, a tandem 3,3‐rearrangement/transannular [4+3] cycloaddition reaction occurred to give propargyl acetates that are regio‐ and diastereospecific. The regiochemistry of the product is controlled by the position of the acetoxy group in the starting material and the stereochemistry of the reaction depends on the ring size. 相似文献
9.
Tatsuhiro Uchikura Mari Oshima Minami Kawasaki Kohei Takahashi Nobuharu Iwasawa 《Angewandte Chemie (International ed. in English)》2020,59(19):7403-7408
Supramolecular photocatalysis via charge‐transfer excitation of a host–guest complex was developed by use of the macrocyclic boronic ester [2+2]BTH‐F containing highly electron‐deficient difluorobenzothiadiazole moieties. In the presence of a catalytic amount of [2+2]BTH‐F, the triplet excited state of anthracene was generated from the charge‐transfer excited state of anthracene@[2+2]BTH‐F by visible‐light irradiation, and cycloaddition of the excited anthracene with several dienes and alkenes proceeded in a [4+2] manner in high yields. 相似文献
10.
Dr. Bjarke S. Donslund Nicolaj Inunnguaq Jessen Giulio Bertuzzi Dr. Maxime Giardinetti Dr. Teresa A. Palazzo Mette Louise Christensen Prof. Dr. Karl Anker Jørgensen 《Angewandte Chemie (International ed. in English)》2018,57(40):13182-13186
The first peri‐ and stereoselective [10+4] cycloaddition between catalytically generated amino isobenzofulvenes and electron‐deficient dienes is described. The highly stereoselective catalytic [10+4] cycloaddition exhibits a broad scope with high yields, reflecting a robust higher‐order cycloaddition. Experimental and computational investigations support a kinetic distribution of intermediate rotamers dictating the enantioselectivity, which relies heavily on additive effects. 相似文献
11.
《Angewandte Chemie (International ed. in English)》2017,56(18):4936-4940
Herein, we describe the first catalytic asymmetric intramolecular [4+2] cycloaddition of in situ generated ortho‐quinone methides. In the presence of a confined chiral imidodiphosphoric acid catalyst, various salicylaldehydes react with dienyl alcohols to give transient ortho ‐quinone methide intermediates, which undergo an intramolecular [4+2] cycloaddition to provide highly functionalized furanochromanes and pyranochromanes in excellent diastereoselectivity and enantioselectivity. 相似文献
12.
Yang‐Zi Liu Zhongao Wang Zesheng Huang Xing Zheng Wu‐Lin Yang Wei‐Ping Deng 《Angewandte Chemie (International ed. in English)》2020,59(3):1238-1242
The palladium‐catalyzed asymmetric [4+3] cyclization of trimethylenemethane donors with benzofuran‐derived azadienes furnishes chiral benzofuro[3,2‐b]azepine frameworks in high yields (up to 98 %) with exclusive regioselectivities and excellent stereoselectivities (up to >20:1 d.r., >99 % ee). This catalytic asymmetric [4+3] cyclization of Pd‐trimethylenemethane can enrich the arsenal of Pd‐TMM reactions in organic synthesis. In addition, this strategy provides an alternative approach to chiral azepines by a transition‐metal‐catalyzed asymmetric [4+3] cyclization. 相似文献
13.
Reversal of the Regiochemistry in the Rhodium‐Catalyzed [4+3] Cycloaddition between Vinyldiazoacetates and Dienes
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Dr. Pablo E. Guzmán Dr. Yajing Lian Prof. Dr. Huw M. L. Davies 《Angewandte Chemie (International ed. in English)》2014,53(48):13083-13087
A regio‐, diastereo‐, and enantioselective [4+3] cycloaddition between vinylcarbenes and dienes has been achieved using the dirhodium tetracarboxylate catalyst [Rh2(S‐BTPCP)4]. This methodology provides facile access to 1,4‐cycloheptadienes that are regioisomers of those formed from the tandem cyclopropanation/Cope rearrangement reaction of vinylcarbenes with dienes. 相似文献
14.
Thermal extrusion of SO2 from β,β′‐sulfolenoporphyrins is an effective method for in situ generation of β,β′‐bis(methylene)porphyrin which remained unobserved in typical synthetic applications but underwent quickly efficient [4+2]‐cycloaddition reactions with dienophiles.We now report the thermal extrusion of SO2 from the symmetrical (tetra‐β,β′‐sulfolenoporphyrinato)zinc 1?Zn in the absence of a dienophile (Scheme). In the event, the thermally in situ generated conjugated diene underwent a [4+2] self‐cycloaddition, to give the {spirobi[tri‐β,β′‐sulfolenoporphyrinato]}dizinc 4?2Zn . This chiral (racemic) spirobiporphyrinoid dizinc complex represents the combination of the closely positioned and interacting chromophores of a (porphyrinato)zinc and of a (β‐methylene‐β,β′‐dihydroporphyrinato)zinc. It carries six sulfoleno moieties that are still available for further SO2 extrusion and cycloaddition reactions. 相似文献
15.
Enantioselective Synthesis of [9]‐ and [11]Helicene‐like Molecules: Double Intramolecular [2+2+2] Cycloaddition
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Yuki Kimura Naohiro Fukawa Yuta Miyauchi Prof. Dr. Keiichi Noguchi Prof. Dr. Ken Tanaka 《Angewandte Chemie (International ed. in English)》2014,53(32):8480-8483
The enantioselective synthesis of completely ortho‐fused [9]‐ and [11]helicene‐like molecules has been achieved through a rhodium‐mediated, intramolecular, double [2+2+2] cycloaddition of phenol‐ or 2‐naphthol‐linked hexaynes. Crystal structures and photophysical properties of these [9]‐ and [11]helicene‐like molecules have also been disclosed. 相似文献
16.
A novel Pd0‐catalyzed asymmetric [4+3] annulation reaction of two readily accessible starting materials has been developed for building seven‐membered heterocyclic architectures. The potential [3+2] side pathway could be suppressed though fine tuning of the conditions. A broad scope of cycloaddition donors and acceptors participated in the transformation with excellent chemo‐, regio‐, diastereo‐, and enantioselectivtities, leading to valuable tetrahydroazepines and benzo[b]oxepines. 相似文献
17.
Reaction of substituted o‐aminobenzyl chlorides with isocyanides in the presence of a weak base (NaHCO3) at room temperature afforded the diversely functionalized 2‐aminoindoles in good to excellent yields. A formal [4+1] cycloaddition of the in situ generated aza‐ortho‐xylylenes with isocyanides accounted for the reaction outcome. 相似文献
18.
Qun‐Liang Zhang Qin Xiong Miao‐Miao Li Wei Xiong Bin Shi Yu Lan Liang‐Qiu Lu Wen‐Jing Xiao 《Angewandte Chemie (International ed. in English)》2020,59(33):14096-14100
Higher‐order cycloadditions, particularly [8+2] cycloadditions, are a straightforward and efficient strategy for constructing significant medium‐sized architectures. Typically, configuration‐restrained conjugated systems are utilized as 8π‐components for higher‐order concerted cycloadditions. However, for this reason, 10‐membered monocyclic skeletons have never been constructed via catalytic asymmetric [8+2] cycloaddition with high peri‐ and stereoselectivity. Here, we accomplished an enantioselective [8+2] dipolar cycloaddition via the merger of visible‐light activation and asymmetric palladium catalysis. This protocol provides a new route to 10‐membered monocyclic architectures bearing chiral quaternary stereocenters with high chemo‐, peri‐, and enantioselectivity. The success of this strategy relied on the facile in situ generation of Pd‐containing 1,8‐dipoles and their enantioselective trapping by ketene dipolarophiles, which were formed in situ via a photo‐Wolff rearrangement. 相似文献
19.
Silvia García‐Rubín Carlos Gonzlez‐Rodríguez Cristina García‐Yebra Jesús A. Varela Miguel A. Esteruelas Carlos Sa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(7):1872-1875
A new synthetic route to dihydrobiphenylenes has been developed. The process involves a mild RuII‐catalyzed [2+2+2] dimerization of ortho‐alkenylarylacetylenes or its more versatile variant, the Ru‐catalyzed [2+2+2] cycloaddition of ortho‐ethynylstyrenes with alkynes. Mechanistic aspects of this [2+2+2] cycloaddition are discussed. 相似文献
20.
RhCl(PPh3)3‐catalyzed [4+2] intramolecular cycloaddition of optically active axially chiral allene‐dienes afforded cis‐fused [3.4.0]‐bicyclic products with three chiral centers in good yields with an excellent chemo‐ and diastereoselectivity. A pair of enantiomers of such products was generated highly selectively from both enantiomers of starting allene‐dienes, indicating that the axial chirality dictated the absolute configurations of the three in situ generated chiral centers with a very high efficiency of chirality transfer. 相似文献