共查询到20条相似文献,搜索用时 15 毫秒
1.
Dr. Youai Qiu Prof.Dr. Jan‐E. Bäckvall 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):2939-2943
An olefin‐directed palladium‐catalyzed regio‐ and stereoselective hydroboration of allenes has been developed to afford fully substituted alkenylboron compounds. The reaction showed a broad substrate scope: a number of functionalized allenes, including 2,3‐dienoate, 3,4‐dienoate, 3,4‐dienol, 1,2‐allenylphosphonate, and alkyl‐substituted allenes, could be used in this olefin‐directed allene hydroboration. The olefin unit was proven to be an indispensable element for this transformation. 相似文献
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Shuifa Qiu Yunyang Wei Prof. Dr. Guosheng Liu Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(12):2751-2754
Taking the air! A PdII‐catalyzed intramolecular hydroamination of allenes coupled to alcohol oxidation has been developed. This reaction is performed by using a nitrogen‐based ligand under aerobic conditions, under which the molecular oxygen is used as the terminal oxidant for the reoxidation of Pd0 species to complete the catalytic cycle.
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Can Li Zheng Yang Lei Wang Yinlong Guo Zheng Huang Shengming Ma 《Angewandte Chemie (International ed. in English)》2020,59(15):6278-6283
An efficient pincer‐ligand‐based cobalt‐complex‐catalyzed allene hydroboration affording Z‐allylic boronates is described. The reaction demonstrates an excellent regio‐ as well as Z‐stereoselectivity and a wide substrate scope that tolerates many functional groups. Based on solvent‐assisted electrospray ionization mass spectrometry (SAESI‐MS) studies, a rationale for the cobalt‐catalyzed hydroboration involving the highly selective insertion of an allene into the Co?H bond to form Z‐allylic cobalt intermediates is proposed. 相似文献
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Dr. Youai Qiu Bin Yang Dr. Can Zhu Prof. Dr. Jan‐E. Bäckvall 《Angewandte Chemie (International ed. in English)》2016,55(22):6520-6524
A highly efficient palladium‐catalyzed oxidative borylation of enallenes was developed for the selective formation of cyclobutene derivatives and fully‐substituted alkenylboron compounds. Cyclobutenes are formed as the exclusive products in MeOH in the presence of H2O and Et3N, whereas the use of AcOH leads to alkenylboron compounds. Both reactions showed a broad substrate scope and good tolerance for various functional groups, including carboxylic acid ester, free hydroxy, imide, and alkyl groups. Furthermore, transformations of the borylated products were conducted to show their potential applications. 相似文献
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Palladium‐Catalyzed Decarboxylative γ‐Arylation for the Synthesis of Tetrasubstituted Chiral Allenes
Ina Scheipers Christian Mück‐Lichtenfeld Armido Studer 《Angewandte Chemie (International ed. in English)》2019,58(20):6545-6548
An enantiospecific palladium‐catalyzed decarboxylative coupling of acyclic β,γ‐alkynoic acids with various aryl iodides to chiral tetrasubstituted allenes is described. The coupling reaction comprises a decarboxylative γ‐palladation of α,α‐disubstituted carboxylic acids to provide the tetrasubstituted allenes with complete point‐to‐axial chirality transfer in excellent yields. 相似文献
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Development of Modifiable Bidentate Amino Oxazoline Directing Group for Pd‐Catalyzed Arylation of Secondary CH Bonds 下载免费PDF全文
Kang Chen Zhao‐Wei Li Peng‐Xiang Shen Dr. Hong‐Wei Zhao Prof. Dr. Zhang‐Jie Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(20):7389-7393
A novel bidentate α‐amino oxazolinyl directing group has been developed. Different from previous directing groups, this newly designed directing group was easily prepared from amino acids and modified in structure. This auxiliary preferentially effects functionalization at secondary C(sp3)?H bonds, rather than at aryl C(sp2)?H bonds. The diastereoselectivity of direct arylation between geminal secondary C(sp3)?H bonds in linear molecules has also been realized for the first time with a chiral directing group by remote chirality relay. Two diastereoisomers are produced with the same chiral source by changing the substituents of substrates and aryl halides. 相似文献
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Yong‐Gang Zhang Xiang‐Lei Liu Zeng‐Yang He Xi‐Ming Li Hong‐Jian Kang Prof. Dr. Shi‐Kai Tian 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(10):2765-2769
An unprecedented oxidative arylation reaction of terminal alkenes with simple aroyl hydrazides has been developed under aerobic conditions for the stereoselective synthesis of 1,2‐disubstituted alkenes. A range of aroyl hydrazides underwent palladium/copper‐catalyzed oxidative Mizoroki–Heck reaction with terminal alkenes open to air in a 1:1 mixture of dimethyl sulfoxide and acetonitrile to give structurally diverse 1,2‐disubstituted alkenes in moderate to excellent yields with excellent regio‐ and E‐selectivity. The reaction tolerated a wide variety of functional groups, such as alkoxy, hydroxy, amino, fluoro, chloro, bromo, cyano, nitro, ester, amide, imide, phosphine oxide, and sulfone groups, and, moreover, molecular oxygen and dimethyl sulfoxide were demonstrated to serve as terminal oxidants. This study provides a useful method for the stereoselective synthesis of 1,2‐disubstituted alkenes through direct transformation of the vinylic C?H bonds in terminal alkenes. 相似文献
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Palladium‐Catalyzed γ‐C(sp3)−H Arylation of Thiols by a Detachable Protecting/Directing Group 下载免费PDF全文
Likun Jin Jianchun Wang Prof. Dr. Guangbin Dong 《Angewandte Chemie (International ed. in English)》2018,57(38):12352-12355
Reported herein is a palladium‐catalyzed, directed γ‐C(sp3)?H arylation of protected thiols. The key is to utilize Michael acceptors as a dual reagent to install a protecting/directing group on thiols by a thiol‐Michael click reaction, and remove it later under basic conditions. The C?H arylation proceeds with high functional‐group tolerance and the deprotected thiols can be further transformed into other sulfur‐containing compounds. This unique mode of activation could open the door for site‐selective functionalization of thiols or other sulfur‐containing compounds at unactivated positions. 相似文献
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Palladium‐Catalyzed Oxidative Arylating Carbocyclization of Allenynes: Control of Selectivity and Role of H2O 下载免费PDF全文
Dipl.‐Chem. Teresa Bartholomeyzik Dr. Javier Mazuela Dr. Robert Pendrill Dr. Youqian Deng Prof. Dr. Jan‐E. Bäckvall 《Angewandte Chemie (International ed. in English)》2014,53(33):8696-8699
Highly selective protocols for the carbocyclization/arylation of allenynes using arylboronic acids are reported. Arylated vinylallenes are obtained with the use of BF3?Et2O as an additive, whereas addition of water leads to arylated trienes. These conditions provide the respective products with excellent selectivities (generally >97:3) for a range of boronic acids and different allenynes. It has been revealed that water plays a crucial role for the product distribution. 相似文献
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Palladium‐Catalyzed Arylation of Unactivated γ‐Methylene C(sp3)H and δ‐CH Bonds with an Oxazoline‐Carboxylate Auxiliary 下载免费PDF全文
Peng‐Xiang Ling Sheng‐Long Fang Xue‐Song Yin Kai Chen Bo‐Zheng Sun Prof. Dr. Bing‐Feng Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17503-17507
A palladium‐catalyzed arylation of unactivated γ‐methylene C(sp3)?H and remote δ‐C?H bonds by using an oxazoline‐carboxylate directing group has been developed. Arylation occurs with a broad substrate scope and high tolerance of functional groups (i.e., halogen, nitro, cyano, ether, trifluoromethyl, amine, and ester). The oxazoline‐type auxiliary can be removed under acidic conditions. 相似文献
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Palladium‐Catalyzed Regio‐ and Stereoselective Chlorothiolation of Terminal Alkynes with Sulfenyl Chlorides 下载免费PDF全文
Dr. Masayuki Iwasaki Tomoya Fujii Arisa Yamamoto Prof. Dr. Kiyohiko Nakajima Prof. Dr. Yasushi Nishihara 《化学:亚洲杂志》2014,9(1):58-62
Chlorothiolation of terminal alkynes with sulfenyl chlorides yields anti‐adducts without transition‐metal catalysts. In sharp contrast, transition‐metal‐catalyzed chlorothiolation has not been developed to date, possibly because organosulfur compounds can poison catalyst. Herein, the regio‐ and stereoselective palladium‐catalyzed chlorothiolation of terminal alkynes with sulfenyl chlorides is described. syn‐Chlorothiolation offers a complementary synthetic route to chloroalkenyl sulfides. 2‐Chloroalkenyl sulfides can easily be transformed into various sulfur‐containing products, most of which are often found in natural products and pharmaceuticals. 相似文献
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Dr. Xiao‐Feng Xia Yu‐Qi Wang Dr. Lu‐Lu Zhang Dr. Xian‐Rong Song Dr. Xue‐Yuan Liu Prof. Dr. Yong‐Min Liang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(17):5087-5091
A new and efficient PdII‐catalyzed intermolecular annulation of N‐benzoylsulfonamide with allenes for the synthesis of 3,4‐dihydroisoquinolin‐1(2H)‐ones is reported. This C?H functionalization is compatible with ambient air and moisture, and it can be applied to terminal or internal allenes with di?erent synthetically attractive functional groups. Control experiments and a kinetic isotope effect study are conducted and a plausible mechanism is proposed. 相似文献
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Enrico Marelli Dr. Martin Corpet Sian R. Davies Prof. Dr. Steven P. Nolan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(52):17272-17276
A general catalytic protocol for the α‐arylation of aryl ketones has been developed. It involves the use of a preformed, bench‐stable Pd–N‐heterocyclic carbene pre‐catalyst bearing IHept as an ancillary ligand, and allows the coupling of various functionalized coupling partners at very low catalyst loading. Careful choice of the solvent/base system was crucial to obtain optimum catalyst performance. The pre‐catalyst was also successfully tested in the synthesis of an industrially relevant compound. 相似文献
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Bo Zhou Dr. Chunhui Jiang Dr. Vasudeva Rao Gandi Prof. Dr. Yixin Lu Prof. Dr. Tamio Hayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(37):13068-13071
Asymmetric arylation of 4‐fluoroalkyl‐2‐quinazolinone derivatives with arylboronic acids proceeded smoothly in the presence of a cationic palladium catalyst (1 mol %) coordinated with a chiral phosphinooxazoline (phox) ligand to create the corresponding fluorine‐containing arylated dihydroquinazolinones in high yields and with greater than 99 % ee. 相似文献
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Can Liu Tao Miao Lei Zhang Prof. Pinhua Li Yicheng Zhang Prof. Lei Wang 《化学:亚洲杂志》2014,9(9):2584-2589
A novel and efficient palladium‐catalyzed C2 arylation of N‐substituted indoles with 1‐aryltriazenes for the synthesis of 2‐arylindoles was developed. In the presence of BF3 ? OEt2 and palladium(II) acetate (Pd(OAc)2), N‐substituted indoles reacted with 1‐aryltriazenes in N,N‐dimethylacetamide (DMAC) to afford the corresponding aryl–indole‐type products in good to excellent yields. 相似文献