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1.
Qiu-Quan Pan Liangliang Qi Dr. Xiaobo Pang Prof. Xing-Zhong Shu 《Angewandte Chemie (International ed. in English)》2023,62(4):e202215703
Catalytic, three-component, cross-electrophile reactions have recently emerged as a promising tool for molecular diversification, but studies have focused mainly on the alkyl-carbonations of alkenes. Herein, the scope of this method has been extended to conjugated dienes and silicon chemistry through silylative difunctionalization of 1,3-dienes with chlorosilanes and aryl bromides. The reaction proceeds under mild conditions to afford 1,2-linear-silylated products, a selectivity that is different to those obtained from conventional methods via an intermediary of H(C)-η3-π-allylmetal species. Preliminary mechanistic studies reveal that chlorosilane reacts with 1,3-diene first and then couples with aryl bromide. 相似文献
2.
Dr. Yi Wei Dr. Quanquan Wang Prof. Dr. Ming Joo Koh 《Angewandte Chemie (International ed. in English)》2023,62(5):e202214247
C-Alkyl glycosides and glycoproteins exist in natural products and are prized for their role as carbohydrate mimics in drug design. However, a practical strategy that merges glycosyl donors with readily accessible reagents, derived from abundant carboxylic acid and amine feedstocks, is yet to be conceived. Herein, we show that a nickel catalyst promotes C−C coupling between glycosyl halides and aliphatic acids or primary amines (converted into redox-active electrophiles in one step), in the presence of Hantzsch ester and LiI (or Et3N) under blue LED illumination to deliver C-alkyl glycosides with high diastereoselectivity. Mechanistic studies support the photoinduced formation of alkyl radicals that react with a glycosyl nickel species generated in situ to facilitate cross-coupling. Through this manifold, innate CO2H and NH2 motifs embedded within amino acids and oligopeptides are selectively capped and functionalized to afford glycopeptide conjugates through late-stage glycosylation. 相似文献
3.
Yusuke Sasano Shota Nagasawa Mai Yamazaki Dr. Masatoshi Shibuya Prof. Dr. Jaiwook Park Prof. Dr. Yoshiharu Iwabuchi 《Angewandte Chemie (International ed. in English)》2014,53(12):3236-3240
The direct oxidation of unprotected amino alcohols to their corresponding amino carbonyl compounds has often posed serious challenges in organic synthesis and has constrained chemists to adopting an indirect route, such as a protection/deprotection strategy, to attain their goal. Described herein is a highly chemoselective aerobic oxidation of unprotected amino alcohols to their amino carbonyl compounds in which 2‐azaadamantane N‐oxyl (AZADO)/copper catalysis is used. The catalytic system developed leads to the alcohol‐selective oxidation of various unprotected amino alcohols, carrying a primary, secondary, or tertiary amino group, in good to high yield at ambient temperature with exposure to air, thus offering flexibility in the synthesis of nitrogen‐containing compounds. 相似文献
4.
An efficient and general approach for the synthesis of amphiphilic 1,2-amino alcohols is reported. The use of N-benzyl protecting groups is essential for obtaining good yields when opening a long-chain terminal epoxide with an amine. 相似文献
5.
Jeremy Brals Dr. Thomas M. McGuire Prof. Dr. Allan J. B. Watson 《Angewandte Chemie (International ed. in English)》2023,62(42):e202310462
We report the development of a C(sp3)−C(sp2) coupling reaction using styrene boronic acids and redox-active esters under photoredox catalysis. The reaction proceeds through an unusual polarity-mismatched radical addition mechanism that is orthogonal to established processes. Synergistic activation of the radical precursor and organoboron are critical mechanistic events. Activation of an N-hydroxyphthalimide (NHPI) ester by coordination to boron enables electron transfer, with decomposition leading to a nucleofuge rebound, activating the organoboron to radical addition. The unique mechanism enables chemoselective coupling of styrene boronic acids in the presence of other alkene radical acceptors. The scope and limitations of the reaction, and a detailed mechanistic investigation are presented. 相似文献
6.
Starting from 2,3-aziridine alcohols, a novel and versatile preparation of optically active amino polyol was achieved using a simple strategy with few purification steps and a good overall yield. 相似文献
7.
Feixiang Sun Jiamin Huang Dr. Zhihong Wei Prof. Dr. Conghui Tang Prof. Dr. Weiping Liu 《Angewandte Chemie (International ed. in English)》2023,62(26):e202303433
A homogeneous manganese-catalyzed cross-coupling of two secondary alcohols for the divergent synthesis of γ-disubstituted alcohols and β-disubstituted ketones is reported. Employing the well-defined Mn-MACHOPh as the catalyst, this novel protocol has a broad substrate scope with good functional group tolerance and affords a diverse library of valuable disubstituted alcohols and ketones in moderate to good yields. The strong influence of the reaction temperature on the selective formation of alcohol products was theorized in preliminary DFT studies. Studies have shown that the Gibbs free energy of the formation of alcohols is thermodynamically more favourable than corresponding ketones at a lower temperature. 相似文献
8.
Hexamethyldisilazane (HMDS) in pesence of a catalytic amount of Envirocat EPZGR silylates different alcohols in high yields with absolute chemoselectivity. 相似文献
9.
Marvin Mendel Dr. Lars Gnägi Uladzislava Dabranskaya Prof. Dr. Franziska Schoenebeck 《Angewandte Chemie (International ed. in English)》2023,62(7):e202211167
While vinyl cyclopropanes are valuable functional groups in drugs or natural products as well as established precursors to trigger a rich variety of synthetic transformations, their reactive nature can make their installation via direct catalytic approaches challenging. We herein present a modular access to (di)vinyl cyclopropanes under very mild conditions and full conservation of stereochemistry, allowing access to the cis or trans cyclopropane- as well as E or Z vinyl-stereochemical relationships. Our protocol relies on air-stable dinuclear PdI catalysis, which enables rapid (<30 min) and selective access to a diverse range of vinyl cyclopropane motifs at room temperature, even on gram scale. 相似文献
10.
Biswanath Das Gurram Mahender Vooturi Sunil Kumar Nikhil Chowdhury 《Tetrahedron letters》2004,45(36):6709-6711
A highly selective method for the cleavage of trityl ethers over a wide range of functional groups has been developed using silica-supported sodium hydrogen sulfate (NaHSO4-SiO2) as a heterogeneous catalyst. The conversion occurred at room temperature and the yields of the alcohols were found to be excellent. 相似文献
11.
Toshitaka Okamura Dr. Syusuke Egoshi Dr. Kosuke Dodo Prof. Dr. Mikiko Sodeoka Prof. Dr. Yoshiharu Iwabuchi Prof. Dr. Naoki Kanoh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(70):16002-16006
Despite the potential of α-fluoroethers in medicinal chemistry, their synthetic methods, especially etherification of aliphatic alcohols, have been limited. Herein, we developed two- and three-step gem-difluoropropargylation of aliphatic alcohols including amino acid derivatives and naturally occurring bioactive molecules. Highly chemoselective etherification proceeded by using the gem-difluoropropargyl bromide dicobalt complex in the presence of silver triflate and triethylamine. Decomplexation of dicobalt complexes was achieved by using cerium ammonium nitrate or N,N,N′-trimethylethylenediamine. The thus obtained gem-difluoropropargyl ethers were converted to various α-difluoroethers which are expected to be useful for medicinal chemistry. 相似文献
12.
Yue Jia Prof. Zhihan Zhang Guo-Ming Yu Xuan Jiang Prof. Liang-Qiu Lu Prof. Wen-Jing Xiao 《Angewandte Chemie (International ed. in English)》2023,62(51):e202312102
The exploration of value-added conversions of naturally abundant amino acids has received considerable attention from the synthetic community. Compared with the well-established asymmetric decarboxylative transformation, the asymmetric deaminative transformation of amino acids still remains a formidable challenge, mainly due to the lack of effective strategies for the C−N bond activation and the potential incompatibility with chiral catalysts. Here, we disclose a photoinduced Cu-catalyzed asymmetric deaminative coupling reaction of amino acids with arylboronic acids. This new protocol provides a series of significant chiral phenylacetamides in generally good yields and excellent stereoselectivity under mild and green conditions (42–85 % yields, up to 97 % ee). Experimental investigations and theoretical calculations were performed to reveal the crucial role of additional phenols in improving catalytic efficiency and enantiocontrol. 相似文献
13.
Manganese porphyrin catalysts supported on different polymer resins were assessed in the selective epoxidation of three dienes. The recyclability of the catalysts was examined. 相似文献
14.
Jillian S. K. Clark Michael J. Ferguson Robert McDonald Mark Stradiotto 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(19):6457-6461
Base‐metal catalysts capable of enabling the assembly of heteroatom‐dense molecules by cross‐coupling of primary heteroarylamines and (hetero)aryl chlorides, while sought‐after given the ubiquity of unsymmetrical di(hetero)arylamino fragments in pharmacophores, are unknown. Herein, we disclose the new “double cage” bisphosphine PAd2‐DalPhos ( L2 ). The derived air‐stable NiII pre‐catalyst C2 functions well at low loadings in challenging test C?N cross‐couplings with established substrates, and facilitates the first Ni‐catalyzed C?N cross‐couplings of primary five‐ or six‐membered ring heteroarylamines and activated (hetero)aryl chlorides, with synthetically useful scope that is competitive with Pd catalysis. 相似文献
15.
Ying Li Wei-Song Zhang Sa-Na Yang Xiao-Yu Wang Yan Liu Ding-Wei Ji Qing-An Chen 《Angewandte Chemie (International ed. in English)》2023,62(17):e202300036
The catalytic bis-allylation of alkynes is an important but challenging protocol to construct all-carbon tetra-substituted alkenes. Particularly, the catalytic unsymmetrical bis-allylation of alkynes remains as an underexplored task to date. We herein report an unprecedented unsymmetrical bis-allylation by simultaneously utilizing electrophilic trifluoromethyl alkene and nucleophilic allylboronate as the allylic reagents. With the aid of robust Ni0/NHC catalysis, valuable skipped trienes can be obtained in high regio- and stereo-selectivities under mild conditions. Mechanistic studies indicate that the reaction may proceed through a β-fluorine elimination of a nickelacycle followed by a transmetalation step with allylboronate. The present method exhibits a good tolerance of various functional groups. Besides, the skipped triene products can undergo an array of elaborate transformations, which highlights the potential applications of this strategy. 相似文献
16.
Farhad Shirini Mohammad Ali Zolfigol Kamal Mohammadi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1567-1570
Reaction of alcohols with hexamethyldisilazane in the presence of silica chloride provides efficiently the corresponding trimethylsilyl ethers. This system discriminates absolutely amines and thiols from alcohols. 相似文献
17.
Direct arylation of adenine with fluoro- and chloronitrobenzenes leads to mixtures of N9 and N7 substituted adenines. After separation by column chromatography, the individual isomers can be efficiently hydrogenated on Pd to give the corresponding aminophenyladenines. A significant enhancement of the reaction rate by microwave irradiation was observed. This two-step procedure was found to be a feasible route to otherwise hardly available 7-aminophenyladenines. Correlation between calculated shielding constants and experimental values of chemical shifts in 13C and 15N NMR was used for assignment of the site of substitution.
[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
18.
Tao Liu Xin-Rui Mao Shuo Song Zi-Yang Chen Dr. Yichen Wu Prof. Dr. Li-Ping Xu Prof. Dr. Peng Wang 《Angewandte Chemie (International ed. in English)》2023,62(11):e202216878
Here, we report the first example of Ni-catalyzed asymmetric hydrosilylation of 1,1-disubstituted allenes with high level of regioselectivities and enantioselectivities. The key to achieve this stereoselective hydrosilylation reaction was the development of the SPSiOL-derived bisphosphite ligands (SPSiPO). This protocol features broad substrate scope, excellent functional group, and heterocycle tolerance, thus provides a versatile method for the construction of enantioenriched tertiary allylsilanes in a straightforward and atom-economic manner. DFT calculations were performed to reveal the reaction mechanism and the origins of the enantioselectivity. 相似文献
19.
Jun Tang Jingxi He Prof. Dr. Sheng-Yin Zhao Prof. Dr. Weiping Liu 《Angewandte Chemie (International ed. in English)》2023,62(17):e202215882
Herein, we report a manganese-catalyzed three-component coupling of secondary alcohols, primary alcohols and methanol for the synthesis of β,β-methylated/alkylated secondary alcohols. Using our method, a series of 1-arylethanol, benzyl alcohol derivatives, and methanol undergo sequential coupling efficiently to construct assembled alcohols with high chemoselectivity in moderate to good yields. Mechanistic studies suggest that the reaction proceeds via methylation of a benzylated secondary alcohol intermediate to generate the final product. 相似文献
20.
Dr. Zhilong Li Dr. Leitao Huan Dr. Jian Li Xiaomin Shu De Zhong Wenjing Zhang Prof. Dr. Haohua Huo 《Angewandte Chemie (International ed. in English)》2023,62(31):e202305889
The cross-electrophile coupling (XEC) represents a powerful strategy for C−C bond formation. However, controlling the enantioselectivity in these processes remains a challenge. Here, we report an unprecedented enantioselective XEC of α-amino acid derivatives with aryl bromides, enabled by alcohols as reducing agents via Ni/photoredox catalysis. This mechanistically distinct approach exploits the ability of photocatalytically generated α-hydroxyalkyl radicals to convert alkyl electrophiles to the corresponding alkyl radicals that are then enantioselectively coupled with aryl bromides. The readily scalable protocol allows modular access to valuable enantioenriched benzylic amines from abundant and inexpensive precursors, and is applicable to late-stage diversification with broad functional group tolerance. Mechanistic studies rationalize the versatility of this alcohol-based reactivity for radical generation and subsequent asymmetric cross-coupling. We expect that this alcohol-based cross-coupling will render a general platform for the development of appealing yet challenging enantioselective XECs. 相似文献