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1.
Lei Wang Kenan Zhang Yuzhuo Wang Wenbo Li Mingjie Chen Junliang Zhang 《Angewandte Chemie (International ed. in English)》2020,59(11):4421-4427
Reported here is a highly efficient Pd/Xiang‐Phos catalyzed enantioselective carboetherification of alkenyl oximes with either aryl or alkenyl halides, delivering various chiral 3,5‐disubstituted and 3,5,5‐trisubstituted isoxazolines in good yields with up to 97 % ee. The sterically bulky and electron‐rich (S,Rs)‐ NMe‐X2 ligand is responsible for the excellent reactivities and enantioselectivities. The salient features of this transformation include mild reaction conditions, general substrate scope, good functional‐group tolerance, good yields, high enantioselectivities, easy scale‐up, and application in the late‐stage modification of bioactive compounds. The obtained products can be readily transformed into useful chiral 1,3‐aminoalcohols. 相似文献
2.
Prof. Dr. Barry M. Trost Dr. Zhijun Zuo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(3):1259-1263
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
3.
Xingye Mu Hanxiao Yu Henian Peng Wenrui Xiong Ting Wu Prof. Dr. Wenjun Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(21):8220-8224
A powerful palladium-catalyzed dearomative cyclization was developed that provides facile access to eight types of bridged tetracyclic skeletons bearing various ring sizes and heterocycles. With this method, several skeletons or analogues of natural products, including tubingensin B and dracaenones, were synthesized. Asymmetric dearomative cyclization enables the construction of various enantiomerically enriched bridged polycyclic systems with up to 99 % ee by employing a chiral palladium catalyst. 相似文献
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5.
Ronan Rocaboy Ioannis Anastasiou Olivier Baudoin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14767-14770
The intramolecular coupling of two C(sp3)?H bonds to forge a C(sp3)?C(sp3) bond is enabled by 1,4‐Pd shift from a trisubstituted aryl bromide. Contrary to most C(sp3)?C(sp3) cross‐dehydrogenative couplings, this reaction operates under redox‐neutral conditions, with the C?Br bond acting as an internal oxidant. Furthermore, it allows the coupling between two moderately acidic primary or secondary C?H bonds, which are adjacent to an oxygen or nitrogen atom on one side, and benzylic or adjacent to a carbonyl group on the other side. A variety of valuable fused heterocycles were obtained from easily accessible ortho‐bromophenol and aniline precursors. The second C?H bond cleavage was successfully replaced with carbonyl insertion to generate other types of C(sp3)‐C(sp3) bonds. 相似文献
6.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(28):8328-8332
Enantioselective nickel‐catalyzed arylative cyclizations of substrates containing a Z ‐allylic phosphate tethered to an alkyne are described. These reactions give multisubstituted chiral aza‐ and carbocycles, and are initiated by the addition of an arylboronic acid to the alkyne, followed by cyclization of the resulting alkenylnickel species onto the allylic phosphate. The reversible E /Z isomerization of the alkenylnickel species is essential for the success of the reactions. 相似文献
7.
Antti Pohjakallio Prof. Petri M. Pihko Ulla M. Laitinen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(37):11325-11339
The formation of 3‐unsubstituted 2‐isoxazolines by means of condensation reactions between α,β‐unsaturated aldehydes and oximes proceeds readily in the presence of catalytic amounts of anilinium salts. Mechanistically, the process involves a fast conjugate addition of the oxime and a slower intramolecular oxime‐transfer reaction. The rate of oxime transfer was found to correlate with the acidity of the catalyst. This finding enabled us to discover an enantioselective process in which the fragile conjugate‐addition product generated in the first stage is rapidly cyclized into the stable isoxazoline under acidic conditions, with conservation of enantiomeric excess. In summary, herein we describe synthetically useful protocols for accessing 3‐unsubstituted 2‐isoxazolines in both the enantioselective and racemic manner. The mechanism of the condensation reaction catalyzed by the anilinium salt was also investigated by NMR spectroscopy experiments in which the effect of differently substituted aldehydes and oximes as well as water on the reaction rate was studied. The results point to the rate‐limiting elimination of water from the 3‐hydroxy‐2‐isoxazolidine intermediate. 相似文献
8.
Huaanzi Hu Fan Teng Jian Liu Weiming Hu Shuang Luo Qiang Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(27):9323-9327
An efficient one‐pot assembly of all‐carbon spiro‐oxindole compounds from non‐oxindole‐based materials has been developed through a palladium‐catalyzed asymmetric Heck/carbonylative lactonization and lactamization sequence. Diversified spirooxindole γ‐and δ‐lactones/lactams were accessed in high yields with good to excellent enantioselectivities (up to 99 % ee) under mild reaction conditions. The natural product coixspirolactam A was conveniently synthesized by applying the current methodology, and thus its absolute configuration was elucidated for the first time. Asymmetric synthesis of an effective CRTH2 receptor antagonist has also been demonstrated utilizing this method in the key step. 相似文献
9.
Dr. Xian-Xiao Chen Hao Luo Ye-Wei Chen Yang Liu Prof. Zhi-Tao He 《Angewandte Chemie (International ed. in English)》2023,62(34):e202307628
Chain walking has been an efficient route to realize the functionalization of inert C(sp3)−H bonds, but this strategy is limited to mono-olefin migration and functionalization. Herein, we demonstrate the feasibility of tandem directed simultaneous migrations of remote olefins and stereoselective allylation for the first time. The adoption of palladium hydride catalysis and secondary amine morpholine as solvent is critical for achieving high substrate compatibility and stereochemical control with this method. The protocol is also applicable to the functionalization of three vicinal C(sp3)−H bonds and thus construct three continuous stereocenters along a propylidene moiety via a short synthetic process. Preliminary mechanistic experiments corroborated the design of simultaneous walking of remote dienes. 相似文献
10.
Lujia Zhou Sanliang Li Dr. Bing Xu Danting Ji Lizuo Wu Prof. Dr. Yu Liu Zhan-Ming Zhang Prof. Dr. Junliang Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(7):2791-2797
Sonogashira-type cross-couplings are one of the most significant alkynylations in organic chemistry. One of the first palladium-catalyzed intramolecular Heck/Sonogashira reactions of alkenes with terminal alkynes is now reported. With this method, a variety of uniquely substituted chiral benzene-fused heterocycles bearing a propargyl-substituted all-carbon quaternary stereocenter were obtained in a straightforward, high-yielding, and highly stereoselective manner under mild conditions. Salient features of this process include the use of readily available substrates, high selectivities, a broad substrate scope as well as versatile product functionalizations. 相似文献
11.
Qiuyu Li Jiajia Li Jie Zhang Shu Wu Yu Zhang Prof. Dr. Aijun Lin Prof. Dr. Hequan Yao 《Angewandte Chemie (International ed. in English)》2023,62(51):e202313404
Bicyclo[3.2.1]octadiene compounds and derivatives exist in a number of natural products and bioactive compounds. Nevertheless, catalytic enantioselective protocols for the synthesis of these skeletons have not been disclosed. Herein we reported a palladium-catalyzed asymmetric intramolecular alkene-alkyne coupling of alkyne-tethered cyclopentenes, affording a library of enantionenriched bicyclo[3.2.1]octadienes in excellent yields and enantioselectivities (mostly >99 % ee). Moreover, the products could undergo an unusual iodination-induced 1,2-acyl migration, forming iodinated bicyclo[3.2.1]octadienes with three vicinal stereocenters. The enone and isolated olefin motifs embedded in the products provide useful handles for downstream elaboration. 相似文献
12.
Dr. Xingfeng Bai Caizhi Wu Prof. Dr. Shaozhong Ge Prof. Dr. Yixin Lu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(7):2786-2790
An asymmetric palladium and copper co-catalyzed Heck/Sonogashira reaction between o-iodoacrylanilides and terminal alkynes to synthesize chiral oxindoles was developed. In particular, a wide range of CF3-substituted o-iodoacrylanilides reacted with terminal alkynes, affording the corresponding chiral oxindoles containing trifluoromethylated quaternary stereogenic centers in high yields with excellent enantioselectivities (94–98 % ee). This asymmetric Heck/Sonogashira reaction provides a general approach to access oxindole derivatives containing quaternary stereogenic centers including CF3-substituted ones. 相似文献
13.
Hiroto Uno Dr. Nagender Punna Etsuko Tokunaga Dr. Motoo Shiro Prof. Norio Shibata 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(21):8264-8271
The two enantiomers of trifluoromethyl-benzo[c][1,5]oxazonines, (R)- 4 and (S)- 4 , can be selectively accessed with high enantiopurity by the Pd-catalyzed ring-expansion reaction of trifluoromethyl-benzo[d][1,3]oxazinones ( 1 ) with vinyl ethylene carbonates ( 3 ) using one antipode of a chiral ligand. Initially, the reaction proceeds by a double decarboxylative ring-expansion with kinetic resolution of 1 in the presence of a Pd-catalyst/chiral ligand to provide (R)- 4 with high enantiopurity. At the same time, the nonreactive antipode of 1 , (S)- 1 , which was recovered with an impeccable s factor of up to 713 and an ideal chemical yield, was transferred into the antipode of the products, (S)- 4 , with high enantiopurity by a second run of the Pd-catalyzed double decarboxylation reaction, but this time without any chiral auxiliary. Thus, both antipodes of the chiral trifluoromethyl heterocycles 4 can be obtained in excellent enantiopurity using only a single antipode of the chiral catalyst. 相似文献
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15.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(26):7583-7586
Palladium‐catalyzed enantioselective dearomative arylalkynylation of N‐substituted indoles, through a Heck/Sonogashira sequence, was established using a new BINOL‐based phosphoramidite as the chiral ligand. A wide range of 2,3‐disubstituted indolines, bearing vicinal quaternary and tertiary stereocenters, were efficiently constructed in one step with excellent enantioselectivities (up to 97 % ee) and diastereoselectivities (>20:1). 相似文献
16.
Dr. Joseph Becica Oliver R. J. Heath Cameron H. M. Zheng Prof. Dr. David C. Leitch 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(39):17430-17434
Carboxylate esters have many desirable features as electrophiles for catalytic cross-coupling: they are easy to access, robust during multistep synthesis, and mass-efficient in coupling reactions. Alkenyl carboxylates, a class of readily prepared non-aromatic electrophiles, remain difficult to functionalize through cross-coupling. We demonstrate that Pd catalysis is effective for coupling electron-deficient alkenyl carboxylates with arylboronic acids in the absence of base or oxidants. Furthermore, these reactions can proceed by two distinct mechanisms for C−O bond activation. A Pd0/II catalytic cycle is viable when using a Pd0 precatalyst, with turnover-limiting C−O oxidative addition; however, an alternative pathway that involves alkene carbopalladation and β-carboxyl elimination is proposed for PdII precatalysts. This work provides a clear path toward engaging myriad oxygen-based electrophiles in Pd-catalyzed cross-coupling. 相似文献
17.
Chao Wang Changpeng Chen Jingyu Zhang Jian Han Qian Wang Kun Guo Pei Liu Mingyu Guan Yingming Yao Yingsheng Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(37):10042-10046
An easily synthesized and accessible N,O‐bidentate auxiliary has been developed for selective C H activation under palladium catalysis. The novel auxiliary showed its first powerful application in C H functionalization of remote positions. Both C(sp2) H and C(sp3) H bonds at δ‐ and ε‐positions were effectively activated, thus giving tetrahydroquinolines, benzomorpholines, pyrrolidines, and indolines in moderate to excellent yields by palladium‐catalyzed intramolecular C H amination. 相似文献
18.
Synthesis of Spirocyclic Ethers by Enantioselective Copper‐Catalyzed Carboetherification of Alkenols 下载免费PDF全文
Shuklendu D. Karyakarte Chanchamnan Um Ilyas A. Berhane Prof. Sherry R. Chemler 《Angewandte Chemie (International ed. in English)》2018,57(39):12921-12924
Spirocyclic ethers can be found in bioactive compounds. This copper‐catalyzed enantioselective alkene carboetherification provides 5,5‐, 5,6‐ and 6,6‐spirocyclic products containing fully substituted chiral carbon centers with up to 99 % enantiomeric excess. This reaction features the formation of two rings from acyclic substrates, 1,1‐disubstituted alkenols functionalized with either arenes, alkenes, or alkynes, and clearly constitutes a powerful way to synthesize chiral spirocyclic ethers. 相似文献
19.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(30):9009-9012
A conceptually novel strategy with achiral pyridine as the ancillary ligand to stabilize high‐valent copper species for the first asymmetric radical oxytrifluoromethylation of alkenes with alcohols under CuI/phosphoric acid dual‐catalysis has been developed. The transformation features mild reaction conditions, a remarkably broad substrate scope and excellent functional group tolerance, offering an efficient approach to a wide range of trifluoromethyl‐substituted tetrahydrofurans bearing an α‐tertiary stereocenter with excellent enantioselectivity. Mechanistic studies support the presumed role of the achiral pyridine as a coordinative ligand on copper metal to stabilize the key transient reaction species involved in the asymmetric induction process. 相似文献