- Optically active lithium-alkoxide catalyzed asymmetric reduction of imines with trimethoxyhydrosilane
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Optically active lithium alkoxide catalyzed asymmetric reduction of imines with trimethoxhydroysilane in moderate enantioselectivity (up to 72% ee).
- Nishikori, Hisashi,Yoshihara, Ritsuko,Hosomi, Akira
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- Asymmetric hydrogenation of N-tosylimines catalyzed by BINAP-ruthenium(II) complexes
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The asymmetric hydrogenation of N-tosylimines was accomplished with a catalytic amount of Ru[(R)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl](O2CCH3)2 to afford the corresponding amines in high enantiomeric excesses.
- Charette, Andre B.,Giroux, Andre
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- Electrochemical synthesis of sulfonamides in a graphite powder macroelectrode
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The electrochemical generation of sulfinyl radicals from commercially available and non-expensive sodium salts of sulfinic acids is described. Electrooxidation reactions were carried out in a graphite powder macroelectrode using an aqueous electrolyte and cavity cell. Further reaction with primary or secondary amines gave the corresponding sulfonamides, a unit present in several biologically active compounds and pharmaceuticals, in good yields.
- Galdino, Danilo,Menezes, Paulo H.,Navarro, Marcelo,Vicente, Dmistocles A.
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supporting information
p. 5262 - 5266
(2020/09/17)
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- Nickel-Catalyzed Asymmetric Transfer Hydrogenation and α-Selective Deuteration of N-Sulfonyl Imines with Alcohols: Access to α-Deuterated Chiral Amines
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A nickel-catalyzed enantioselective transfer hydrogenation and deuteration of N-sulfonyl imines was developed. Excellent α-selectivity and high deuterium content were achieved by using inexpensive 2-propanol-d8 as a deuterium source. As a highlight, no deuteration of β-C-H and the remote C-H of N-sulfonyl amines occurred, which is hard to achieve using other imines or by hydrogen isotope exchange with D2O. Mechanism studies indicated a stepwise pathway through the [Ni-D] intermediate.
- Yang, Peng,Zhang, Li,Fu, Kaiyue,Sun, Yaxin,Wang, Xiuhua,Yue, Jieyu,Ma, Yu,Tang, Bo
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supporting information
p. 8278 - 8284
(2020/11/03)
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- Asymmetric Stepwise Reductive Amination of Sulfonamides, Sulfamates, and a Phosphinamide by Nickel Catalysis
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Asymmetric reductive amination of poorly nucleophilic sulfonamides was realized in the presence of nickel catalysts and titanium alkoxide. A wide range of ketones, including enolizable ketones and some biaryl ones, were converted into sulfonamides in excellent enantiomeric excess. The cyclization of sulfamates and intermolecular reductive amination of a diarylphosphinamide were also successful. Formic acid was used as a safe and economic surrogate of high-pressure hydrogen gas.
- Zhao, Xiaohu,Xu, Haiyan,Huang, Xiaolei,Zhou, Jianrong Steve
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p. 292 - 296
(2018/12/13)
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- Enantioselective Hydrogenation of Activated Aryl Imines Catalyzed by an Iron(II) P-NH-P′ Complex
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Chiral amines are key building blocks in synthetic chemistry with numerous applications in the agricultural and pharmaceutical industries. Asymmetric imine hydrogenation, particularly with iridium catalysts, is well developed. However, imine reduction still remains challenging in the context of replacing such a precious metal with a cheap, nontoxic, and environmentally friendly substitute such as iron. Here, we report that an unsymmetrical iron P-NH-P′ catalyst that was previously shown to be effective for the asymmetric hydrogenation of aryl ketones is also a very effective catalyst for the asymmetric hydrogenation of prochiral aryl imines activated with N-diphenylphosphinoyl or N-tosyl groups. The P-NH-P′ abbreviation stands for (S,S)-PPh2CHPhCHPhNHCH2CH2PiPr2. Density functional theory results suggest that, surprisingly, the NH group on the catalyst activates and orients the imine to hydride attack by hydrogen bonding to the PO or SO group on the imine nitrogen, as opposed to the imine nitrogen itself. This may explain why N-Ph and N-Bu imines are not hydrogenated.
- Seo, Chris S. G.,Tannoux, Thibault,Smith, Samantha A. M.,Lough, Alan J.,Morris, Robert H.
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p. 12040 - 12049
(2019/10/02)
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- PTAB mediated open air synthesis of sulfonamides, thiosulfonates and symmetrical disulfanes
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A facile methodology has been described which has successfully simplified the generation of sulfonamides, thiosulfonates and symmetric disulfanes. This “trio” of reactions occur in an open air metal free atmosphere and has also been scaled up to grams making it suitable for commercialization. The reactions also have been successfully carried out with asymmetric variants, thus contributing to the chiral pool. The user friendly “trio” enables easy generation of these versatile sulfur analogues and the reaction condition employed depict an economic outline.
- Sarkar, Debayan,Ghosh, Manoj Kumar,Rout, Nilendri
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supporting information
p. 2360 - 2364
(2018/05/24)
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- Highly Efficient One-Pot Synthesis of Novel Propargylamine-Based Sulfonamides by an A3-Coupling Reaction
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Novel propargylamine-based sulfonamides were synthesized in excellent yields by the copper(I) iodide catalyzed three-component coupling of propargylsulfonamides, morpholine, and aldehydes.
- Abdoli, Morteza,Saeidian, Hamid,Kakanejadifard, Ali
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p. 2473 - 2476
(2016/10/24)
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- Nickel-catalyzed asymmetric transfer hydrogenation of hydrazones and other ketimines
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We report the use of nickel catalysts for the catalytic transfer hydrogenation of hydrazones and other ketimines with formic acid. Strongly donating bisphosphines must be used to support the catalysts. As in enzymatic catalysis, attractive weak interactio
- Xu, Haiyan,Yang, Peng,Chuanprasit, Pratanphorn,Hirao, Hajime,Zhou, Jianrong
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p. 5112 - 5116
(2015/04/27)
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- Chiral N-Heterocyclic Carbene Ligands Bearing a Pyridine Moiety for the Copper-Catalyzed Alkylation of N-Sulfonylimines with Dialkylzinc Reagents
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Amino acid-derived chiral imidazolium salts, each bearing a pyridine ring, were developed as N-heterocyclic carbene ligands. The copper-catalyzed asymmetric alkylation of various N-sulfonylimines with dialkylzinc reagents in the presence of these chiral imidazolium salts afforded the corresponding alkylated products with high enantioselectivity (up to 99 % ee). The addition of HMPA to the reaction mixture as a co-solvent is critical in terms of chemical yield and enantioselectivity. A wide range of N-sulfonylimines and dialkylzinc reagents were found to be applicable to this reaction. Amino acid-derived chiral imidazolium salts, each bearing a pyridine ring, were developed as N-heterocyclic carbene ligands. The copper-catalyzed asymmetric alkylation of various N-sulfonylimines with dialkylzinc reagents in the presence of these chiral imidazolium salts afforded the corresponding alkylated products with high enantioselectivity (up to 99 % ee; see scheme). A wide range of N-sulfonylimines and dialkylzinc reagents were found to be applicable to this reaction.
- Soeta, Takahiro,Ishizaka, Tomohiro,Tabatake, Yuta,Ukaji, Yutaka
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supporting information
p. 16773 - 16778
(2016/02/18)
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- Palladium-catalyzed intramolecular oxidative coupling involving double C(sp2)-H bonds for the synthesis of annulated biaryl sultams
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The palladium-catalyzed intramolecular oxidative coupling described herein involves a double C(sp2)-H bond functionalization in sulfonanilides, providing a workable access to biaryl sultams annulated into a six-membered ring that are otherwise difficult to obtain by literature methods. The other synthetic applications of this protocol including the synthesis of biaryl sultams containing a seven-membered ring and analogous sultones are also presented.
- Laha, Joydev K.,Jethava, Krupal P.,Dayal, Neetu
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p. 8010 - 8019
(2015/03/18)
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- Asymmetric transfer hydrogenation of ketimines using well-defined iron(II)-based precatalysts containing a PNNP ligand
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Well-defined iron(II)-based complexes containing PNNP ligands catalyze a highly enantioselective reduction of N-(diphenylphosphinoyl)- and N-(p-tolylsulphonyl)-ketimines. Under mild conditions and low catalyst loading, the ketimines are successfully reduced to the corresponding amines in enantiomeric excess ranging from 94 to 99%.
- Mikhailine, Alexandre A.,Maishan, Mazharul I.,Morris, Robert H.
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supporting information
p. 4638 - 4641
(2012/10/29)
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- Highly enantioselective Rh-catalyzed transfer hydrogenation of N-sulfonyl ketimines
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Several imine species comprising N-sulfinyl and N-sulfonyl ketimine, oxime, and enamine derivatives were subjected to asymmetric transfer hydrogenation in an azeotropic mixture of formic acid/triethylamine. Among them, the Rh-catalyzed transfer hydrogenat
- Kwak, Se Hun,Lee, Sun Ah,Lee, Kee-In
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experimental part
p. 800 - 804
(2010/10/21)
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- Ligand-assisted, copper-catalyzed enantioselective benzylic amination
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Several classes of ligands, including α-amino acids, diamines, diphosphines, bis-oxazolines, and diimines, support efficient copper-catalyzed amination of benzylic hydrocarbons by anhydrous chloramine-T. Catalysts derived from homochiral ligands, particularly chiral diimines, effect aminosulfonation with low to moderate enantioselectivity.
- Barman, Dipti N.,Nicholas, Kenneth M.
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supporting information; experimental part
p. 1815 - 1818
(2010/09/07)
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- Enantioselective synthesis, configurational stability, and reactivity of lithium α-tert-butylsulfonyl carbanion salts
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The reactions of enantiopure S-tert-butyl sulfones of the type R 1CH(R2)SO2tBu (≥99% ee) with lithiumorganyl compounds gave the corresponding chiral α-sulfonyl carbanion salts [R 1C(R2)SO2tBu]Li with ≥94% ee. The enantioselectivity of the deprotonation of the phenyl- but not dialkyl-substituted sulfones is strongly dependent on the nature of the lithiumorganyl. Because of this observation and the strong decrease in enantioselectivity in the presence of TMEDA and HMPA, we propose an intramolecular proton transfer following complexation of the sulfone by RLi. Racemization of [R1C(R2)-SO2tBu]Li follows first-order kinetics and seems to be mainly an enthalpic process with a small negative activation entropy, as revealed by polarimetric measurements at low temperatures. This is in accordance with Cα-S bond rotation as the rate-determining step. The salts [R1C(R2)SO 2tBu]Li have half-lives of racemization in the order of several hours at -105°C. The deuteriation of the salts at -105°C with CF 3CO2D proceeded with enantioselectivities of 94% ee, the magnitude of which was not significantly affected by the presence of TMEDA and HMPA. The salts also reacted with carbon-based electrophiles at low temperatures with high enantioselectivity. The conversion of R1CH(R 2)SO2tBu via [R1C(R2)SO 2tBu]Li to R1C(R2,E)SO2tBu, which involves the loss of stereogenicity at the α-stereogenic center and its reestablishment upon reaction of the chiral carbanion with electrophiles, occurred with high overall enantioselectivity. Electrophiles attack the anionic C atom of [R1C(R2)SO2tBu]Li with high selectivity on the side syn to the O atoms and anti to the tert-butyl group. The reactivity of the dialkyl-substituted salts [R1C(R 2)SO2tBu]Li (R1, R2 = alkyl) is significantly higher than that of the benzylic salts [RC(Ph)SO2tBu]Li (R = alkyl) and the HMPA-coordinated SIPs of [MeC(Ph)SO2- tBu]Li are significantly more reactive towards EtI than the corresponding O-Li contact ion pairs.
- Scholz, Roland,Hellmann, Gunther,Rohs, Susanne,Oezdemir, Diana,Raabe, Gerhard,Vermeeren, Cornelia,Gais, Hans-Joachim
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scheme or table
p. 4588 - 4616
(2010/10/21)
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- Highly enantioselective Pd-catalyzed asymmetric hydrogenation of activated imines
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(Chemical Equation Presented) Pd/bisphosphines complexes are highly effective catalysts for asymmetric hydrogenation of activated imines in trifluoroethanol. The asymmetric hydrogenation of N-diphenylphosphinyl ketimines 3 with Pd(CF3CO2)/(S)-SegPhos indicated 87-99% ee, and N-tosylimines 5 could gave 88-97% ee with Pd-(CF3CO 2)/(S)-SynPhos as a catalyst. Cyclic N-sulfonylimines 7 and 11 were hydrogenated to afford the useful chiral sultam derivatives in 79-93% ee, which are important organic synthetic intermediates and structural units of agricultural and pharmaceutical agents.
- Wang, You-Qing,Lu, Sheng-Mei,Zhou, Yong-Gui
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p. 3729 - 3734
(2008/02/04)
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- Asymmetric addition of dimethylzinc to N-tosylarylimines catalyzed by a rhodium-diene complex toward the synthesis of chiral 1-arylethylamines
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A rhodium complex coordinated with a chiral diene, (R,R)-2,5- diphenylbicyclo[2.2.2]octa-2,5-diene (Ph-bod*), catalyzed the asymmetric addition of dimethylzinc to N-tosylarylimines to give high yields of chiral 1-aryl-1-ethylamines with high enantioselectivity (94-98% ee).
- Nishimura, Takahiro,Yasuhara, Yuichi,Hayashi, Tamio
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p. 979 - 981
(2007/10/03)
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- Mild deprotection of primary N-(p-toluenesulfonyl) amides with SmI 2 following trifluoroacetylation
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A mild deprotection method for notoriously difficult to unmask primary N-(p-toluenesulfonyl) amides was developed during our total synthesis studies toward the marine toxin, gymnodimine. The deprotection occurs at low temperature (-78 °C) under mild conditions by initial activation of the nitrogen with a trifluoroacetyl group, followed by reductive cleavage of the p-toluenesulfonyl group with samarium diiodide. The substrate scope and functional group tolerance of this useful N-S cleavage process, which builds on related cleavage processes of other nitrogen-heteroatom bonds, is explored. Georg Thieme Verlag Stuttgart.
- Moussa, Ziad,Romo, Daniel
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p. 3294 - 3298
(2008/09/17)
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- Asymmetric Alkylation of N-Toluenesulfonylimines with Dialkylzinc Reagents Catalyzed by Copper-Chiral Amidophosphine
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The synthetic procedure of a chiral amidophosphine ligand 5 bearing two bulky substituents, 2,4,6-trimethylphenylmethyl or 2,4,6-triisopropylphenylmethyl groups, on the pyrrolidine ring was improved by employing the borane-THF reduction of the lactam-alco
- Soeta, Takahiro,Nagai, Kazushige,Fujihara, Hidetaka,Kuriyama, Masami,Tomioka, Kiyoshi
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p. 9723 - 9727
(2007/10/03)
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- Enantioselective fluorination of organic molecules. I. synthetic studies of the agents for electrophilic, enantioselective fluorination of carbanions
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In order to develop novel methods for electrophilic and enantioselective fluorination of active methine compounds, preliminary experiments were carried out. The N-tosyl derivative 5 obtained from D-phenylglycine was fluorinated with FC1O3 or di
- Takeuchi, Yoshio,Satoh, Akira,Suzuki, Takanori,Kameda, Ayako,Dohrin, Masahiro,Satoh, Toshihiro,Koizumi, Toru,Kirk, Kenneth L.
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p. 1085 - 1088
(2007/10/03)
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- Asymmetric Induction in the Reduction of Optically Active N-Alkylidenesulphinamides by Metal Hydrides. A New, Efficient Enantioselective Route to Chiral Amines
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A series of racemic and optically active N-alkylidenesulphinamides has been prepared and their reduction by metal hydrides studied.The extent of asymmetric synthesis mainly depends on the nature of the reducing species; the best results (up to 92percent of stereoselectivity) are obtained with alkoxy-lithium aluminium hydrides.A new, highly enantioselective synthesis of amines is described.
- Annunziata, Rita,Cinquini, Mauro,Cozzi, Franco
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p. 339 - 344
(2007/10/02)
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