948-99-2Relevant academic research and scientific papers
Regioselective Synthesis of α-Functional Stilbenes via Precise Control of Rapid cis- trans Isomerization in Flow
Lee, Hyune-Jea,Yonekura, Yuya,Kim, Nayoung,Yoshida, Jun-Ichi,Kim, Heejin
, p. 2904 - 2910 (2021/05/05)
The rapid cis-trans isomerization of α-anionic stilbene was regioselectively controlled by using flow microreactors, and its reaction with various electrophiles was conducted. The reaction time was precisely controlled within milliseconds to seconds at -50 °C to selectively give the cis- or trans-isomer in high yields. This synthetic method in flow was well-applied to synthesize precursors of commercial drug compound, (E)- and (Z)-tamoxifen with high regioselectivity and productivity.
Iridium-Catalyzed Hydrochlorination and Hydrobromination of Alkynes by Shuttle Catalysis
Yu, Peng,Bismuto, Alessandro,Morandi, Bill
supporting information, p. 2904 - 2910 (2020/01/25)
Described herein are two different methods for the synthesis of vinyl halides by a shuttle catalysis based iridium-catalyzed transfer hydrohalogenation of unactivated alkynes. The use of 4-chlorobutan-2-one or tert-butyl halide as donors of hydrogen halides allows this transformation in the absence of corrosive reagents, such as hydrogen halides or acid chlorides, thus largely improving the functional-group tolerance and safety profile of these reactions compared to the state-of-the-art. This method has granted access to alkenyl halide compounds containing acid-sensitive groups, such as tertiary alcohols, silyl ethers, and acetals. The synthetic value of those methodologies has been demonstrated by gram-scale synthesis where low catalyst loading was achieved.
Iodine(III)-Mediated Oxidative Hydrolysis of Haloalkenes: Access to α-Halo Ketones by a Release-and-Catch Mechanism
Jobin-Des Lauriers, Antoine,Legault, Claude Y.
supporting information, p. 108 - 111 (2016/01/15)
An unprecedented iodine(III)-mediated oxidative transposition of vinyl halides has been accomplished. The products obtained, α-halo ketones, are useful and polyvalent synthetic precursors. There are only a handful of reported examples of the direct conversion of vinyl halides to their corresponding α-halo carbonyl compounds. Insights into the mechanism and demonstration that this synthetic transformation can be done under enantioselective conditions are reported.
Selective Ruthenium-Catalyzed Hydrochlorination of Alkynes: One-Step Synthesis of Vinylchlorides
Dérien, Sylvie,Klein, Hubert,Bruneau, Christian
supporting information, p. 12112 - 12115 (2015/10/12)
An unprecedented ruthenium-catalyzed direct and selective alkyne hydrochlorination is reported and leads to vinylchlorides in excellent yields with atom economy. The reaction proceeds at room temperature from terminal alkynes and provides a variety of chloroalkenes. Only the regioisomer resulting from the formal Markovnikov addition is selectively formed. Mechanistic studies show the stereoselective syn addition of HCl to alkynes at room temperature and suggest a chloro hydrido RuIV species as a key intermediate of the reaction.
Iridium-catalyzed addition of aroyl chlorides and aliphatic acid chlorides to terminal alkynes
Iwai, Tomohiro,Fujihara, Tetsuaki,Terao, Jun,Tsuji, Yasushi
supporting information; experimental part, p. 1268 - 1274 (2012/03/12)
Iridium complexes show high catalytic activity in intermolecular additions of acid chlorides to terminal alkynes to afford valuable (Z)-β-chloro- α,β-unsaturated ketones. Ligands in the catalytic system play a crucial role in this reaction. An N-heterocyclic carbene (NHC) is an efficient ligand for the addition of aroyl chlorides, while dicyclohexyl(2-methylphenyl) phosphine (PCy2(o-Tol)) is indispensable for the reaction of aliphatic acid chlorides. The addition reactions proceed regio- and stereoselectively with suppression of decarbonylation and β-hydrogen elimination, which have been two major intrinsic problems in transition-metal-catalyzed reactions. Stoichiometric reactions of active iridium catalysts with aroyl chlorides and aliphatic acid chlorides are carried out to gain insights into the reaction mechanisms.
Bis- N -heterocyclic carbene palladium(IV) tetrachloride complexes: Synthesis, reactivity, and mechanisms of direct chlorinations and oxidations of organic substrates
McCall, A. Scott,Wang, Hongwang,Desper, John M.,Kraft, Stefan
scheme or table, p. 1832 - 1848 (2011/04/15)
This Article describes the preparation and isolation of novel octahedral CH2-bridged bis-(N-heterocyclic carbene)palladium(IV) tetrachlorides of the general formula LPdIVCl4 [L = (NHC)CH 2(NHC)] from LPdIICl2 and Cl2. In intermolecular, nonchelation-controlled transformations LPdIVCl 4 reacted with alkenes and alkynes to 1,2-dichlorination adducts. Aromatic, benzylic, and aliphatic C-H bonds were converted into C-Cl bonds. Detailed mechanistic investigations in the dichlorinations of alkenes were conducted on the 18VE PdIV complex. Positive solvent effects as well as kinetic measurements probing the impact of cyclohexene and chloride concentrations on the rate of alkene chlorination support a PdIV-Cl ionization in the first step. Product stereochemistry and product distributions from various alkenes also support Cl+-transfer from the pentacoordinated PdIV-intermediate LPdIVCl 3+ to olefins. 1-Hexene/3-hexene competition experiments rule out both the formation of π-complexes along the reaction coordinate as well as in situ generated Cl2 from a reductive elimination process. Instead, a ligand-mediated direct Cl+-transfer from LPd IVCl3+ to the π-system is likely to occur. Similarly, C-H bond chlorinations proceed via an electrophilic process with in situ formed LPdIVCl3+. The presence of a large excess of added Cl- slows cyclohexene chlorination while the presence of stoichiometric amounts of chloride accelerates both PdIV-Cl ionization and Cl+-transfer from LPdIVCl3 +. 1H NMR titrations, T1 relaxation time measurements, binding isotherms, and Job plot analysis point to the formation of a trifurcated Cl-...H-C bond in the NHC-ligand periphery as a supramolecular cause for the accelerated chemical events involving the metal center.
Palladium(0)-catalyzed cross-coupling of potassium (z)-2-chloroalk-1-enyl trifluoroborates: A chemo- and stereoselective access to (z)-chloroolefins and trisubstituted alkenes
Guinchard, Xavier,Bugaut, Xavier,Cook, Cyril,Roulland, Emmanuel
supporting information; experimental part, p. 5793 - 5798 (2010/01/15)
We describe the preparation of a series of new potassium trifluoroborates 1 and the study of their behaviour in a Pd0-catalyzed cross-coupling reaction. We found that compounds 1 are endowed with original properties as they behave as nucleophil
Mesoionic carbenes: Reactions of 1, 3-diphenyltetrazol-5-ylidene with electron-deficient alkenes, and synthesis and catalytic activities of the (tetrazol-5-ylidene)rhodium(I) complexes
Araki, Shuki,Yokoi, Keisaku,Sato, Ryosuke,Hirashita, Tsunehisa,Setsune, Jun-Ichiro
scheme or table, p. 164 - 171 (2009/07/17)
The reactions of 1, 3-diphenyltetrazol-5-ylidene, a rare example of mesoionic carbenes, with electron- deficient unsaturated compounds were studied. The carbene reacted with dimethyl 1, 2, 4, 5-tetrazine-3, 6-dicarboxylate to give a 5-tetrazoliomethylide, together with hydrazine derivatives. The reaction with tetracyanoethylene gave another methylide in low yield. On the contrary, the reactions with weaker electrophiles, such as 3, 6-diphenyl-1, 2, 4, 5-tetrazine, fumalonitrile, N-phenylmaleimide, and dimethyl acetylenedicarboxylate, did not give any coupling products, but gave phenylated products and/or Michael addition products via the degradation of the 1, 3-diphenyltetrazole ring. Novel mesoionic mono- and bis(carbene)-rhodium(I) complexes were synthesized and the structures were characterized by X-ray crystallography. Their catalytic activities for the decarbonylative addition reaction of benzoyl chloride to ethynylbenzene were investigated.
Iridium-catalyzed addition of acid chlorides to terminal alkynes
Iwai, Tomohiro,Fujihara, Tetsuaki,Terao, Jun,Tsuji, Yasushi
supporting information; experimental part, p. 6668 - 6669 (2009/10/30)
(Chemical Equation Presented) An iridium N-heterocyclic carbene (NHC) complex, IrCl(cod)(IPr), successfully catalyzed an addition of common aromatic acid chlorides to terminal alkynes to afford (Z)-β-chloro-α,β- unsaturated ketones regio- and stereoselectively. When the NHC ligand (IPr) was changed to a phosphine (RuPhos), the addition occurred with decarbonylation to give the corresponding (Z)-vinyl chlorides. Furthermore, the former reaction using IrCl(cod)(IPr) can be applied to the catalytic synthesis of 2,5-disubstituted furans.
First catalytic and green synthesis of aryl-(Z)-vinyl chlorides and its plausible addition-elimination mechanism
Su, Weike,Jin, Can
, p. 993 - 996 (2007/10/03)
(Chemical Equation Presented) Via a catalytic cycle in the presence of scandium triflate (2 mol %)/DMF (1 mol %)/benzoyl chloride (5 mol %), aromatic ketones were treated with bis(trichloromethyl) carbonate (BTC) to afford aryl-(Z)-vinyl chlorides. All metal triflates tested in the reaction showed highly catalytic activity. A plausible addition-elimination mechanism was proposed. The present work describes the first catalytic and green route to the synthesis of aryl-(Z)-vinyl chlorides.
