- Copper-Catalyzed 1,1-Boroalkylation of Terminal Alkynes: Access to Alkenylboronates via a Three-Component Reaction
-
A copper-catalyzed three-component reaction of terminal alkynes, diazo compounds, and B2pin2 to prepare trisubstituted alkenylboronates has been developed. This difunctionalization of alkynes selectively occurs at the terminal carbon atom and proceeds via
- Li, Ziyong,Sun, Jiangtao
-
supporting information
p. 3706 - 3711
(2021/05/31)
-
- Copper on charcoal: Cu0nanoparticle catalysed aerobic oxidation of α-diazo esters
-
By using a charcoal supported nano Cu0catalyst (Cu/C), a highly efficient oxidation of α-diazo esters to α-ketoesters with molecular oxygen as the sole oxidant has been developed. In the presence of the Cu/C catalyst, 2-aryl-α-diazo esters with both electron-donating and electron-withdrawing groups can be oxidized to the corresponding α-ketoesters efficiently. Furthermore, this Cu/C catalyst can catalyse the reaction of aryl α-diazo ester with water to form aryl ketoester, 2-aryl-2-hydroxyl acetate ester and 2-aryl acetate ester. In this case, water is split by α-diazo ester, and the diazo group is displaced by the oxygen or hydrogen atom in water. Mechanistic investigation showed that the reaction of α-diazo ester with oxygen proceeds through a radical pathway. In the presence of 2,2,6,6-tetramethyl piperidine nitrogen oxide, the reaction of α-diazo ester with oxygen is dramatically inhibited. Furthermore, the reaction of α-diazo ester with water is investigated by an isotopic tracer method, and GCMS detection showed that a disproportionation reaction occurred between α-diazo ester and water.
- Chu, Changhu,Dong, Wenwen,Lin, Jia,Teng, Jiangge,Wang, Zhiwei,Zhao, Rong
-
p. 6120 - 6126
(2021/07/21)
-
- Blue Light-Promoted Formal [4+1]-Annulation of Diazoacetates with o-Aminoacetophenones: Synthesis of Polysubstituted Indolines and Computational Study
-
A blue light-promoted formal [4+1]-annulation of diazoacetates with o-aminoacetophenones has been reported, which provides an environmentally friendly method for the synthesis of polysubstituted indoline derivatives in moderate to good yields with excellent diastereoselectivities. Detailed mechanistic studies through density functional theory calculations reveal that the (E)-enol species is the key intermediate in this transformation, and the excellent diastereoselectivity is enabled via H-bonding in the intramolecular Aldol-type addition.
- Chen, Jinzhou,Liu, Shuhao,Lv, Xinxin,Hong, Kemiao,Lei, Jinping,Xu, Xinfang,Hu, Wenhao
-
p. 13920 - 13928
(2020/11/03)
-
- A gold(i)-catalysed chemoselective three-component reaction between phenols, α-diazocarbonyl compounds and allenamides
-
Gold(i) catalysts are considered to be efficient in promoting sp2 C-H bond insertion at the para position of unprotected phenols because of the exceptionally chemical reactivity of gold-stabilized carbophilic carbocations. Herein, we present a
- Yu, Sifan,Chen, Jinzhou,Liu, Gengxin,Lei, Jinping,Hu, Wenhao,Qiu, Huang
-
supporting information
p. 1649 - 1652
(2020/02/18)
-
- Tridentate Nickel(II)-Catalyzed Chemodivergent C-H Functionalization and Cyclopropanation: Regioselective and Diastereoselective Access to Substituted Aromatic Heterocycles
-
A Schiff-base nickel(II)-phosphene-catalyzed chemodivergent C-H functionalization and cyclopropanation of aromatic heterocycles is reported in moderate to excellent yields and very good regioselectivity and diastereoselectivity. The weak, noncovalent interaction between the phosphene ligand and Ni center facilitates the ligand dissociation, generating the electronically and coordinatively unsaturated active catalyst. The proposed mechanisms for the reported reactions are in good accord with the experimental results and theoretical calculations, providing a suitable model of stereocontrol for the cyclopropanation reaction.
- Nag, Ekta,Gorantla, Sai Manoj N. V. T.,Arumugam, Selvakumar,Kulkarni, Aditya,Mondal, Kartik Chandra,Roy, Sudipta
-
p. 6313 - 6318
(2020/09/02)
-
- Planar chiral [2.2]paracyclophane-based bisoxazoline ligands and their applications in Cu-Mediated N-H insertion reaction
-
New catalysts for important C-N bond formation are highly sought after. In this work, we demonstrate the synthesis and viability of a new class of planar chiral [2.2]paracyclophane-based bisoxazoline (BOX) ligands for the copper-catalyzed N-H insertion of α-diazocarbonyls into anilines. The reaction features a wide substrate scope and moderate to excellent yields, and delivers the valuable products at ambient conditions.
- Knoll, Daniel M.,Hu, Yuling,Hassan, Zahid,Nieger, Martin,Br?se, Stefan
-
-
- Ketenimine Formation Catalyzed by a High-Valent Cobalt Carbene in Bulky Alkoxide Ligand Environment
-
High-valent cobalt carbene Co(OR)2(CPh2) (OR = OCtBu2Ph) undergoes reaction with various isocyanides CNR (CNR = 2,6-dimethylphenyl isocyanide, 4-methoxyphenyl isocyanide, 2-chloro-6-methylphenyl isocyanide, adamantyl isocyanide) to yield the corresponding ketenimine. The reaction is accompanied by the formation of cobalt bis(alkoxide) bis(isocyanide) complexes Co(OR)2(CNR)2, which were independently synthesized and characterized. DFT calculations suggest the mechanism proceeds through isocyanide binding to Co, followed by intramolecular insertion into the Co-carbene bond to form the ketenimine. We have also conducted an investigation of the catalytic formation of ketenimines at room temperature using mixtures of diazoalkanes (diphenyldiazomethane, methyl diazo(phenyl)acetate, and ethyl diazoacetate) and isocyanides (2,6-dimethylphenyl isocyanide, 4-methoxyphenyl isocyanide, adamantyl isocyanide, cyclohexyl isocyanide, and benzyl isocyanide). While no catalytic reactivity was observed for diphenyldiazomethane, ester-substituted diazoalkanes (diazoesters) demonstrate catalytic turnover. Relatively high yields are observed for the reactions involving bulkier aliphatic substrates adamantyl and cyclohexyl isocyanides. Mechanistic studies suggest that the lack of catalytic reactivity involving diphenyldiazomethane results from the inability of Co(OR)2(CNR)2 to undergo carbene formation upon reaction with N2CPh2. In contrast, facile reaction is observed between Co(OR)2(CNR)2 and diazoesters, which enables the overall catalytic reactivity.
- Grass, Amanda,Dewey, Nicholas S.,Lord, Richard L.,Groysman, Stanislav
-
p. 962 - 972
(2019/02/26)
-
- Selective Vinylogous Reactivity of Carbene Intermediate in Gold-Catalyzed Alkyne Carbocyclization: Synthesis of Indenols
-
A gold-catalyzed carbocyclization of alkynes with a pendant diazo group that is completed by reaction with a protic nucleophile for the synthesis of indenol derivatives with a tertiary center is described. Mechanistic studies and DFT calculations indicate
- Zhang, Cheng,Li, Hongli,Pei, Chao,Qiu, Lihua,Hu, Wenhao,Bao, Xiaoguang,Xu, Xinfang
-
p. 2440 - 2447
(2019/03/08)
-
- Ru(II)-Catalyzed Cross-Coupling of Cyclopropenes with Diazo Compounds: Formation of Olefins from Two Different Carbene Precursors
-
Formal carbene dimerization is a convergent method for the synthesis of alkenes. Herein, we report a Ru(II)-catalyzed carbene dimerization of cyclopropenes and diazo compounds. The yields are up to 97% and the stereoselectivity are up to >20:1. Mechanistically, it has been experimentally demonstrated that the catalyst reacts with cyclopropene first to generate a Ru(II)-carbene species, which is attacked by nucleophilic diazo substrate, followed by dinitrogen extrusion to form the double bond.
- Wang, Bo,Yi, Heng,Zhang, Hang,Sun, Tong,Zhang, Yan,Wang, Jianbo
-
p. 1026 - 1032
(2018/01/28)
-
- Stereoselective Synthesis of Tetrasubstituted Furylalkenes via Gold-Catalyzed Cross-Coupling of Enynones with Diazo Compounds
-
A stereoselective, gold-catalyzed, cross-coupling reaction of enynones with diazo compounds has been developed, affording 2-alkenylfurans in moderate to good yields with excellent E-stereoselectivity. Upon using diazo compounds as nucleophiles to trap the in situ formed gold furyl carbene, this protocol provides a novel path toward the formation of unsymmetrical tetrasubstituted alkenes.
- Liu, Pei,Sun, Jiangtao
-
p. 3482 - 3485
(2017/07/15)
-
- (C6F5)3B Catalyzed Chemoselective and ortho-Selective Substitution of Phenols with α-Aryl α-Diazoesters
-
The development of an efficient method for the site-selective substitution of unprotected phenols has long been considered as an attractive but challenging task. Herein, we describe a highly chemo- and ortho-selective substitution reaction of phenols with α-aryl α-diazoacetates with commercially available (C6F5)3B as the catalyst. This reaction proceeds under simple and mild conditions with high efficiency, it features a wide substrate scope and can be easily scaled up.
- Yu, Zhunzhun,Li, Yongfeng,Shi, Jiameng,Ma, Ben,Liu, Lu,Zhang, Junliang
-
p. 14807 - 14811
(2016/11/23)
-
- Gold-catalyzed construction of two adjacent quaternary stereocenters via sequential C-H functionalization and aldol annulation
-
Herein, a novel and efficient gold-catalyzed intermolecular C(sp2)-H functionalization (Friedel-Crafts alkylation) and aldol annulation strategy is presented. This cascade process allows the synthesis of a series of indanol and tetrahydronaphthalenol derivatives with two adjacent quaternary stereocenters. The attractive reaction features are the use of readily available starting materials, good diastereoselectivity, good functional-group tolerance and mild reaction conditions. Furthermore, preliminary results indicate that this transformation is amenable to enantioselectivitive synthesis with further chiral ligand screening and design.
- Yu, Zhunzhun,Qiu, Haile,Liu, Lu,Zhang, Junliang
-
supporting information
p. 2257 - 2260
(2016/02/12)
-
- Gold(I)-catalyzed diazo coupling: Strategy towards alkene formation and tandem benzannulation
-
A gold(I)-catalyzed cross-coupling of diazo compounds to afford tetrasubstituted alkenes has been developed by taking advantage of a trivial electronic difference between two diazo substrates. A N-heterocyclic-carbene-derived gold complex is the most effective catalyst for this transformation. Based on this new strategy a gold(I)-initiated benzannulation has been achieved through a tandem reaction involving a diazo cross-coupling 6πelectrocyclization and oxidative aromatization.
- Zhang, Daming,Xu, Guangyang,Ding, Dong,Zhu, Chenghao,Li, Jian,Sun, Jiangtao
-
p. 11070 - 11074
(2015/03/30)
-
- Iridium porphyrin catalyzed N-H insertion reactions: Scope and mechanism
-
Ir(TTP)CH3 catalyzed N-H insertion reactions between ethyl diazoacetate (EDA) or methyl phenyldiazoacetate (MPDA) and a variety of aryl, aliphatic, primary, and secondary amines to generate substituted glycine esters with modest to high yields. Aniline substrates generally gave yields above 80%, with up to 105 catalyst turnovers, and without slow addition of the diazo reagent. Good yields were also achieved with aliphatic amines, though higher catalyst loadings and slow addition of the amine were necessary in some cases. Primary amines reacted with EDA to generate both single- and double-insertion products, either of which could be produced selectively in high yield with the proper choice of stoichiometric ratios and reaction temperature. Notably, mixed trisubstituted amines, RN(CH2CO2Et) (CHPhCO2Me), were generated from the insertion of 1 equiv of EDA and 1 equiv of MPDA into primary amines. The N-H insertion mechanism was examined using substrate competition studies, trapping experiments, and multiple spectroscopic techniques. Substrate competition studies using pairs of amines with EDA or MPDA revealed Hammett correlations with respective slopes of ρ = 0.15 and ρ+ = -0.56 as well as kinetic isotope ratios of k H/kD = 1.0 ± 0.2 and 2.7 ± 0.2. Competitive amine binding to the iridium center was demonstrated by kinetics and equilibrium binding studies. Equilibrium binding constants ranged from 102 to 105. Monitoring the reaction by absorption spectroscopy revealed a transient metalloporphyrin complex. The lifetime of this species was dependent on the nature of the amine substrate, which suggests that the catalytic cycle proceeds through a metal-ylide intermediate.
- Anding, Bernie J.,Woo, L. Keith
-
p. 2599 - 2607
(2013/06/26)
-
- Copper-catalyzed synthesis of 2,4-disubstituted allenoates from α-diazoesters
-
Chemical equations presented. A Cu-catalyzed method for coupling α-substituted-α-diazoesters with terminal alkynes to give substituted allenoates is described. Key to the development of a selective method was the recognition that an adventitous base catalyzes the isomerization to form the allenoate product. A plausible mechanism is proposed, based in part on evidence against a mechanism that involves a Cu(I)-acetylide as a low-valent intermediate.
- Hassink, Matthew,Liu, Xiaozhong,Fox, Joseph M.
-
scheme or table
p. 2388 - 2391
(2011/06/25)
-
- Reactions of diazo compounds with alkenes catalysed by [RuCl(cod)(Cp)]: Effect of the substituents in the formation of cyclopropanation or metathesis products
-
The reaction of diazo compounds with alkenes catalysed by complex [RuCl(COd)(Cp)] (cod = 1, 5-cyclooctadiene, Cp = cyclopentadienyl) has been studied. The catalytic cycle involves in the first step the decomposition of the diazo derivative to afford the reactive [RuCl(Cp)I=C(R1)R 2)] intermediate and a mechanism is proposed for this step based on a kinetic study of the simple coupling reaction of ethyl diazoacetate. The evolution of the Ru-carbene intermediate in the presence of alkenes depends on the nature of the substituents at both the diazo N2=C(R 1)R2 (R1, R2 = Ph, H; Ph, CO 2Me; Ph, Ph; C(R1)R2 = fluorene) and the olefin substrates R3(H)C= C(H)R4 (R3, R4 = CO2Et, CO2Et; Ph, Ph; Ph, Me; Ph, H; Me, Br; Me, CN; Ph, CN; H, CN; CN, CN). A remarkable reactivity of the complex was recorded, especially towards unstable aryldiazo compounds and electron-poor olefins. The results obtained indicate that either cyclopropanation or metathesis products can be formed: the first products are favoured by the presence of a cyano substituent at the double bond and the second ones by a phenyl.
- Basato, Marino,Tubaro, Cristina,Biffis, Andrea,Bonato, Marco,Buscemi, Gabriella,Lighezzolo, Filippo,Lunardi, Pamela,Yianini, Chiara,Benetollo, Franco,Del Zotto, Alessandro
-
experimental part
p. 1516 - 1526
(2009/09/04)
-
- The rhodium catalyzed three-component reaction of diazoacetates, titanium(IV) alkoxides and aldehydes
-
The rhodium(n)-catalyzed three-component reaction of diazoacetates, titanium alkoxides and aldehydes is shown to give α-alkoxyl-β- hydroxyl acid derivatives; the novel C-C bond formation reaction is proposed to occur through oxonium ylides derived from diazo compounds and titanium alkoxides, and followed by intermolecular trapping by aldehydes. The Royal Society of Chemistry 2005.
- Lu, Chong-Dao,Liu, Hui,Chen, Zhi-Yong,Hu, Wen-Hao,Mi, Ai-Qiao
-
p. 2624 - 2626
(2007/10/03)
-
- The thionophosphate-thiolophosphate photoisomerization proceeds predominantly through a non-chain radical pathway. Synthetically viable benzylation of tetrahydrofuran, propan-2-ol and olefins
-
The photoirradiation of thionophosphates, ROP(S)(OEt)2, derived from benzyl and vinylogously benzyl alcohols in CH3CN, with a Hanovia medium-pressure mercury lamp in a quartz vessel leads to the formation of the corresponding thiolophosphates, RSP(O)(OEt)2, through a non-chain radical pathway. This behavior of thionophosphates is unlike that of the related phosphates, which react through ionic dissociation-recombination processes. When the irradiation is conducted in solvents such as PriOH, THF and toluene, benzylation of these solvents takes place in synthetically respectable yields. Irradiation of thionophosphates in CH3CN leads to a convenient allylic benzylation of olefins.
- Yadav, Veejendra K.,Balamurugan, Rengarajan,Parvez, Masood,Yamdagni, Raghav
-
p. 323 - 332
(2007/10/03)
-
- Catalytic Asymmetric C-H Activation of Alkanes and Tetrahydrofuran
-
Rhodium carbenoids derived from methyl aryldiazoacetates are capable of effective catalytic asymmetric C-H activation of a range of alkanes and tetrahydrofuran by a C-H insertion mechanism. Dirhodium tetrakis(S-(N-dodecylbenzenesulfonyl)prolinate) (Rh2(S-DOSP)4) catalyzed decomposition of methyl aryldiazoacetates in the presence of alkanes results in intermolecular C-H insertions with good control of regioselectivity, diastereoselectivity, and enantioselectivity. The carbenoids derived from methyl aryldiazoacetates are considerably more chemoselective than carbenoids derived from diazoacetates. They strongly favor C-H insertions into secondary and tertiary sites. Formation of side products due to carbene dimerization is not a major problem with rhodium carbenoids derived from aryldiazoacetates.
- Davies, Huw M. L.,Hansen, Tore,Churchill, Melvyn Rowen
-
p. 3063 - 3070
(2007/10/03)
-
- Reductive homo-coupling of methyl 2-Br-2-Cl-carboxylates promoted by CuBr-Fe0
-
Dimethyl 2,3-dialkyl-2,3-dichloro-butanedioates are efficiently prepared in dimethylformamide or dimethylsulphoxide, through reductive homo-coupling of methyl 2-bromo-2-chlorocarboxylates promoted by CuBr-Fe0.
- Benincasa, Marta,Forti, Luca,Ghelfi, Franco,Pagnoni, Ugo M.
-
p. 1103 - 1106
(2007/10/02)
-
- The Low-temperature Photolysis of Diazo Compounds. The Utility of Tertiary Alcohol in Matrix Studies of Carbene Chemistry
-
Carbene processes within the t-BuOH matrix at -196 deg C were investigated in order to show the utility of the matrix as a tool for the study of carbene chemistry.The photolysis of several aryldiazomethane derivatives in the t-BuOH matrix gave the olefinic dimer as the main product, probably arising from a combination of two triplet arylcarbenes in the aggregate of molecules.The similar photolysis of other diazo compounds (e.g., N2CHCOR, R = OR', NEt2, and Ph) resulted in no detection of the olefinic dimer.This was explained in terms of the structural effect on the ground-state multiplicity of carbene.The photolysis of Ph2CN2 in t-BuOH containing 5percent EtOH at -196 deg C gave almost exclusively O-H and C-H insertion products with the solute alcohol at the expense of the O-H insertion product with the host, i.e., Ph2CHOBut, which was the major product in the liquid-phase photolysis.This is ascribable to the co-aggregation of the carbene precursor with the solute alcohol because of the relatively large guest hole provided by the bulky tertiary alcohol matrix.A more general utility of this matrix was shown in the reaction of Ph2C with Ph2CO to give oxirane, in which the intervention of carbonyl ylide was demonstrated at low temperatures.
- Tomioka, Hideo,Miwa, Takaaki,Suzuki, Shinji,Izawa, Yasuji
-
p. 753 - 756
(2007/10/02)
-