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1.
Yasuaki Kawaguchi Dr. Shigeo Yasuda Akira Kaneko Yuki Oura Prof. Dr. Chisato Mukai 《Angewandte Chemie (International ed. in English)》2014,53(29):7608-7612
The efficient RhI‐catalyzed cycloisomerization of benzylallene‐alkynes produced the tricyclo[9.4.0.03,8]pentadecapentaene skeleton through a C? H bond activation in good yields. A plausible reaction mechanism proceeds via oxidative addition of the acetylenic C? H bond to RhI, an ene‐type cyclization to the vinylidenecarbene–RhI intermediate, and an electrophilic aromatic substitution with the vinylidenecarbene species. It was proposed based on deuteration and competition experiments. 相似文献
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Rhodium(I)‐Catalyzed Cycloisomerization of Homopropargylallene‐Alkynes through C(sp3)−C(sp) Bond Activation 下载免费PDF全文
Yasuaki Kawaguchi Kenya Yabushita Prof. Dr. Chisato Mukai 《Angewandte Chemie (International ed. in English)》2018,57(17):4707-4711
Upon exposure to a catalytic amount of [RhCl(CO)2]2 in 1,4‐dioxane, homopropargylallene‐alkynes underwent a novel cycloisomerization accompanied by the migration of the alkyne moiety of the homopropargyl functional group to produce six/five/five tricyclic compounds in good yields. A plausible mechanism was proposed on the basis of an experiment with 13C‐labeled substrate. The resulting tricyclic derivatives were further converted into the corresponding bicyclo[3.3.0] skeletons with vicinal cis dihydroxy groups. 相似文献
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Prof. Dr. Takanori Matsuda Kotaro Kato Tsuyoshi Goya Shingo Shimada Prof. Dr. Masahiro Murakami 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):1941-1943
A ruthenium complex catalyzes a new cycloisomerization reaction of 2,2′‐diethynylbiphenyls to form 9‐ethynylphenanthrenes, thereby cleaving the carbon–carbon triple bond of the original ethynyl group. A metal–vinylidene complex is generated from one of the two ethynyl groups, and its carbon–carbon double bond undergoes a [2+2] cycloaddition with the other ethynyl group to form a cyclobutene. The phenanthrene skeleton is constructed by the subsequent electrocyclic ring opening of the cyclobutene moiety. 相似文献
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Xiao‐Lin Lu Dr. Mao‐Yun Lyu Prof. Dr. Xiao‐Shui Peng Prof. Dr. Henry N. C. Wong 《Angewandte Chemie (International ed. in English)》2018,57(35):11365-11368
A novel gold‐catalyzed tandem protocol, initiated by hydride transfer in the presence of catalytic (C6F5)3PAuCl/AgSbF6, for the formation of fused polycyclic ring systems has been achieved. This tandem reaction provides rapid access to various fused polycyclic species in a single chemical operation, leading to stereospecific formation of two carbon–carbon bonds and three rings. 相似文献
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Construction of Hexahydrophenanthrenes By Rhodium(I)‐Catalyzed Cycloisomerization of Benzylallene‐Substituted Internal Alkynes through C−H Activation 下载免费PDF全文
Yasuaki Kawaguchi Dr. Shigeo Yasuda Prof. Dr. Chisato Mukai 《Angewandte Chemie (International ed. in English)》2016,55(35):10473-10477
The treatment of benzylallene‐substituted internal alkynes with [RhCl(CO)2]2 effects a novel cycloisomerization by C(sp2)?H bond activation to produce hexahydrophenanthrene derivatives. The reaction likely proceeds through consecutive formation of a rhodabicyclo[4.3.0] intermediate, σ‐bond metathesis between the C(sp2)?H bond on the benzene ring and the C(sp2)?RhIII bond, and isomerization between three σ‐, π‐, and σ‐allylrhodium(III) species, which was proposed based on experiments with deuterated substrates. 相似文献
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Charles Fehr Dr. Beat Winter Iris Magpantay 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(38):9773-9784
We describe in detail a direct, stereoselective synthesis of (?)‐cubebol based on a Pt‐, Au‐, or Cu‐catalyzed cycloisomerization in which control of the configuration of the propargylic center is essential for the facial selectivity. In addition, we show that cycloisomerization reactions of enantioenriched propargyl pivalates occur with substantial chirality transfer. We confirm a mechanism by means of cyclization followed by an [1,2]‐acyl migration for the Pt‐ and the Au‐catalyzed cycloisomerization. So far, no evidence supports that the Cu‐catalyzed cycloisomerization follows the same reaction course. 相似文献
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Nicolas Marion Dr. Gilles Lemière Andrea Correa Chiara Costabile Rubén S. Ramón Xavier Moreau Dr. Pierre de Frémont Dr. Rim Dahmane Alexandra Hours Dr. Denis Lesage Jean‐Claude Tabet Prof. Dr. Jean‐Philippe Goddard Dr. Vincent Gandon Dr. Luigi Cavallo Prof. Dr. Louis Fensterbank Prof. Dr. Max Malacria Prof. Dr. Steven P. Nolan Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(13):3243-3260
Ester‐way to heaven : Unexpected formation of bicyclo[3.1.0]hexene 4 was the main focus of combined experimental and theoretical studies on the Au‐catalyzed cycloisomerization of branched dienyne 1 (see scheme), which provided better understanding of the mechanistic details governing the cyclization of enynes bearing a propargylic ester group.
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Gold‐Catalyzed Cycloisomerization and Diels–Alder Reaction of 1,4,9‐Dienyne Esters to 3 a,6‐Methanoisoindole Esters with Pro‐Inflammatory Cytokine Antagonist Activity 下载免费PDF全文
Dewi Susanti Li‐Juan Liu Dr. Weidong Rao Sheng Lin Prof. Dr. Dik‐Lung Ma Prof. Dr. Chung‐Hang Leung Prof. Dr. Philip Wai Hong Chan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(25):9111-9118
A synthetic method to prepare 3a,6‐methanoisoindole esters efficiently by gold(I)‐catalyzed tandem 1,2‐acyloxy migration/Nazarov cyclization followed by Diels–Alder reaction of 1,4,9‐dienyne esters is described. We also report the ability of one example to inhibit binding of tumor necrosis factor‐α (TNF‐α) to the tumor necrosis factor receptor 1 (TNFR1) site and TNF‐α‐induced nuclear factor κ‐light‐chain‐enhancer of activated B cells (NF‐κB) activation in cell at a half‐maximal inhibitory concentration (IC50) value of 6.6 μM . Along with this is a study showing the isoindolyl derivative to exhibit low toxicity toward human hepatocellular liver carcinoma (HepG2) cells and its possible mode of activity based on molecular modeling analysis. 相似文献
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Dr. Nitin T. Patil 《化学:亚洲杂志》2012,7(10):2186-2194
Over the last few years, gold‐catalyzed reactions that involved chirality transfer and memory of chirality (MOC) have emerged as a powerful tool in enantioselective synthesis. This technique has allowed for the single‐step synthesis of enantioenriched compounds from readily available starting materials. This Focus Review discusses this emerging field with an emphasis on mechanistic aspects and their applications in synthetic organic chemistry. 相似文献
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Fang Wang Prof. Dr. Chuan‐Liang Feng 《Angewandte Chemie (International ed. in English)》2018,57(20):5655-5659
For chiral hydrogels and related applications, one of the critical issues is how to control the chirality of supramolecular systems in an efficient way, including easy operation, efficient transfer of chirality, and so on. Herein, supramolecular chirality of l ‐phenylalanine based hydrogels can be effectively controlled by using a broad range of metal ions. The degree of twisting (twist pitch) and the diameter of the chiral nanostructures can also be efficiently regulated. These are ascribed to the synergic effect of hydrogen bonding and metal ion coordination. This study may develop a method to design a new class of electronically, optically, and biologically active materials. 相似文献
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Hierarchical Self‐Assembly in Liquid‐Crystalline Block Copolymers Enabled by Chirality Transfer 下载免费PDF全文
Shuai Huang Yuxuan Chen Shudeng Ma Prof. Dr. Haifeng Yu 《Angewandte Chemie (International ed. in English)》2018,57(38):12524-12528
Helical topological structures are often found in chiral biological systems, but seldom in synthesized polymers. Now, controllable microphase separation of amphiphilic liquid‐crystalline block copolymers (LCBCs) consisting of hydrophilic poly(ethylene oxide) and hydrophobic azobenzene‐containing poly(methylacrylate) is combined with chirality transfer to fabricate helical nanostructures by doping with chiral additives (enantiopure tartaric acid). Through hydrogen‐bonding interactions, chirality is transferred from the dopant to the aggregation, which directs the hierarchical self‐assembly in the composite system. Upon optimized annealing condition, helical structures in film are fabricated by the induced aggregation chirality. The photoresponsive azobenzene mesogens in the LCBC assist photoregulation of the self‐assembled helical morphologies. This allows the construction and non‐contact manipulation of complicated nanostructures. 相似文献
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Dr. Xu Deng Shao‐Fei Ni Zheng‐Yu Han Yu‐Qing Guan Prof. Dr. Hui Lv Prof. Dr. Li Dang Prof. Dr. Xu‐Mu Zhang 《Angewandte Chemie (International ed. in English)》2016,55(21):6295-6299
An enantioselective rhodium(I)‐catalyzed cycloisomerization reaction of challenging (E)‐1,6‐enynes is reported. This novel process enables (E)‐1,6‐enynes with a wide range of functionalities, including nitrogen‐, oxygen‐, and carbon‐tethered (E)‐1,6‐enynes, to undergo cycloisomerization with excellent enantioselectivity, in a high‐yielding and operationally simple manner. Moreover, this RhI‐diphosphane catalytic system also exhibited superior reactivity and enantioselectivity for (Z)‐1,6‐enynes. A rationale for the striking reactivity difference between (E)‐ and (Z)‐1,6‐enynes using RhI‐BINAP and RhI‐TangPhos is outlined using DFT studies to provide the necessary insight for the design of new catalyst systems and the application to synthesis. 相似文献
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Zhiyong Wu Kévin Isaac Dr. Pascal Retailleau Dr. Jean‐François Betzer Dr. Arnaud Voituriez Dr. Angela Marinetti 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(10):3278-3281
The key structural feature of the new phosphoramidites is a paracyclophane scaffold in which two aryl rings are tethered by both a 1,8‐biphenylene unit and a O?P?O bridge. Suitable aryl substituents generate planar chirality. The corresponding gold(I) complexes promote the cycloisomerization of prochiral nitrogen‐tethered dienynes. These reactions afford bicyclo[4.1.0]heptene derivatives displaying three contiguous stereogenic centers, with very high diastereoselectivity and up to 95 % ee. 相似文献
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Prof. Dr. Weidong Rao Joshua William Boyle Prof. Dr. Philip Wai Hong Chan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6532-6536
A synthetic method that relies on a gold(I)‐catalyzed cycloisomerization of 1‐en‐3,9‐diyne esters to spiro[4.4]non‐2‐ene‐substituted 1,2‐dihydronaphthalenes is described. Robust with a wide variety of substitution patterns tolerated, the reaction provides the first example of a one‐step strategy to construct such novel and architecturally challenging members of the carbocycle family in good to excellent yields. A mechanism is proposed in which the sequential cycloisomerization pathway was thought to involve a gold‐catalyzed 1,3‐acyloxy migration/Nazarov cyclization followed by a formal [4+2] cycloaddition to give the tetracarbocyclic product. 相似文献
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Gold(I)‐Catalyzed Intramolecular Cycloisomerization of Propargylic Esters with Furan Rings 下载免费PDF全文
Jin‐Ming Yang Prof. Dr. Xiang‐Ying Tang Prof. Dr. Min Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(12):4534-4540
A gold‐catalyzed intramolecular cycloisomerization of α‐yne‐furans 1 is described in this contribution. A variety of cyclic α,β‐unsaturated aldehyde or ketone derivatives and nitrogen‐containing tricyclic adducts were obtained selectively in moderate to excellent yields under mild conditions by varying the substituents on the standard substrates. 相似文献