- Enantioselective Construction of Sulfur-Containing Tetrasubstituted Stereocenters via Asymmetric Functionalizations of α-Sulfanyl Cyclic Ketones
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Asymmetric functionalizations of α-sulfanyl cyclic ketones were realized via chiral phosphoric acid catalyzed enantioselective addition reactions with aldimines, azodicarboxylates and allenamides. A series of chiral organosulfur compounds possessing sulfur-containing tetrasubstituted stereocenters were accessed via these methods, with excellent regioselectivities and high stereoselectivities. (Figure presented.).
- Ye, Xueqian,Pan, Yongkai,Chen, Yunrong,Yang, Xiaoyu
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p. 3374 - 3379
(2020/07/16)
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- γ-Selective Vinylogous Aza-Morita-Baylis-Hillman Reaction with N -Carbamoylimines
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Vinylogous aza-Morita-Baylis-Hillman (aza-MBH) reactions of a vinylcyclopentenone with N -Boc imines provide the corresponding γ-adducts in high regioselectivity (10 examples). While the corresponding reactions with N -Ts imines give the α-adducts and γ-a
- Gondo, Naruhiro,Tanigaki, Yusuke,Ueda, Yoshihiro,Kawabata, Takeo
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p. 398 - 402
(2020/02/27)
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- Silver-Catalyzed Enantioselective Mannich Reaction of Diazoacetate Esters with N-Boc Aldimines
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The highly enantioselective Mannich reaction of diazoacetate esters with N-Boc aldimines catalyzed by silver(I) triflate in the presence of (R)-DM-SEGPHOS is reported. The reaction is broad in scope with respect to the (hetero)aromatic aldehyde-derived al
- Robertson, Gerard P.,Farley, Alistair J. M.,Dixon, Darren J.
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p. 2785 - 2792
(2020/02/04)
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- Direct enantioselective Mannich reactions of α-azido cyclic ketones: Asymmetric construction of chiral azides possessing an α-quaternary stereocenter
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Direct enantioselective Mannich reactions of α-azido cyclic ketones with aldimines are realized through chiral phosphoric acid catalysis, which generate chiral azides possessing an α-quanternary stereocenter with complete regioselectivities and high diast
- Ye, Xueqian,Pan, Yongkai,Yang, Xiaoyu
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- Two Distinct Ag(I)- And Au(I)-Catalyzed Olefinations between α-Diazo Esters and N-Boc-Derived Imines
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Metal-catalyzed reactions between α-diazo esters and imines were well-known to yield aziridine derivatives exclusively. This work reports two new olefination reactions between N-Boc-derived (Boc = tert-Butyloxycarbonyl) imines and α-diazo esters with Ag(I) and Au(I) catalysts, respectively. Our mechanistic studies reveal that these new olefinations involve an initial attack of diazo esters on metal/imine complexes to form Mannich-addition intermediates, which subsequently afford α-aryl-β-aminoacrylates via a Roskamp reaction, or to form β-aryl-β-aminoacrylates via the formation of silver carbenes.
- Kardile, Rahul Dadabhau,Liu, Rai-Shung
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p. 6452 - 6456
(2019/09/06)
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- Direct Catalytic Asymmetric Mannich-Type Reaction en Route to α-Hydroxy-β-amino Acid Derivatives
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A direct catalytic Mannich-type reaction of α-oxygen-functionalized amides was achieved. The use of 7-azaindoline amide was crucial to facilitate direct enolization and subsequent stereoselective addition to imines in a cooperative catalytic system comprising a soft Lewis acid and Br?nsted base. The operationally simple room-temperature protocol furnished a syn-Mannich adduct with high stereoselectivity. Divergent functional group transformation of the amide moiety of the product allowed for expeditious access to enantioenriched syn-configured α-hydroxy-β-amino carboxylic acid derivatives, highlighting the synthetic utility of the present catalysis.
- Sun, Bo,Pluta, Roman,Kumagai, Naoya,Shibasaki, Masakatsu
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p. 526 - 529
(2018/02/10)
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- Copper-catalyzed borylative coupling of vinylazaarenes and N-Boc imines
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Cu-catalyzed three-component couplings of vinylazaarenes, B2(pin)2, and N-Boc imines are described. Oxidation of the initially formed boronate gives azaarene-containing, Boc-protected amino alcohols with reasonable to good diastereoselectivities.
- Smith, Joshua J.,Best, Daniel,Lam, Hon Wai
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p. 3770 - 3772
(2016/03/22)
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- Efficient synthesis of α-(N-Boc)aminoamides by addition of a carbamoylsilane to N-Boc-imines
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N,N-Dimethylcarbamoyl(trimethyl)silane reacted with N-Boc-imines in anhydrous benzene under catalysts-free conditions to afford N-Boc-protected α-amino amides in good yields (72-89%). The electronic property and the steric hindrance of substituent on the N-Boc-imines affected the reaction.
- Guo, Qilin,Wen, Xueping,Chen, Jianxin
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p. 8117 - 8122
(2016/11/19)
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- Enantioselective copper-catalyzed reductive coupling of vinylazaarenes with n -boc aldimines
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The diastereo- and enantioselective reductive coupling of vinylazaarenes with N-Boc aldimines is described. The reactions proceed using chiral copper-bisphosphine complexes in the presence of TMDS as a hydride source to give reductive coupling products in moderate to high enantioselectivities.
- Choi, Bonnie,Saxena, Aakarsh,Smith, Joshua J.,Churchill, Gwydion H.,Lam, Hon Wai
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p. 350 - 354
(2015/02/19)
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- Copper(I)-Catalyzed Asymmetric Pinacolboryl Addition of N-Boc-imines Using a Chiral Sulfoxide - Phosphine Ligand
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Highly efficient and enantioselective copper(I)-catalyzed pinacolboryl addition of N-Boc-imines is reported. By using a single chiral sulfoxide-(dialkyl)phosphine (SOP) ligand, both enantiomeric isomers of α-amino boronic esters were obtained through an achiral counteranion switch.
- Wang, Ding,Cao, Peng,Wang, Bing,Jia, Tao,Lou, Yazhou,Wang, Min,Liao, Jian
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p. 2420 - 2423
(2015/05/27)
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- Asymmetric disulfonimide-catalyzed synthesis of δ-amino-β-ketoester derivatives by vinylogous Mukaiyama-Mannich reactions
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An organocatalytic asymmetric synthesis of δ-amino-β-ketoester derivatives has been developed. A chiral disulfonimide (DSI) serves as a highly efficient precatalyst for a vinylogous Mukaiyama-Mannich reaction of readily available dioxinone-derived silylox
- Wang, Qinggang,Van Gemmeren, Manuel,List, Benjamin
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p. 13592 - 13595
(2015/01/09)
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- Construction of chiral quaternary carbon center via catalytic asymmetric aza-Henry reaction with α-substituted nitroacetates
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The catalytic enantioselective aza-Henry reaction of N-Boc aldimines 2 and 2-nitropropionic acid ethyl ester 3 in the mixed solvents of toluene-saturated brine (10:1) was catalyzed by cinchona quaternary ammonium salts to form a new quaternary carbon center. High yields (up to 90%), and excellent enantioselectivities (up to 99% ee) and diastereoselectivity ratio (up to 22:1) were successfully obtained with mild conditions. This journal is the Partner Organisations 2014.
- Li, Minghua,Ji, Nan,Lan, Ting,He, Wei,Liu, Rui
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p. 20346 - 20350
(2014/06/09)
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- Asymmetric mannich reaction of malonates with aldimines using YbIII-pybox complexes supported on self-assembled organic-inorganic hybrid silica with an imidazolium framework
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Yb(OTf)3/iPr-pybox (3b) immobilized on a self-assembled organic-inorganic hybrid silica with ionic liquid phase (SAILP) (Catalyst A) behaves as an efficient and recyclable catalyst in the enantioselective Mannich reaction of malonate esters wit
- Karimi, Babak,Jafari, Ehsan,Enders, Dieter
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supporting information
p. 7253 - 7258
(2015/02/02)
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- Asymmetric synthesis of anti -β-amino-α-hydroxy esters via dynamic kinetic resolution of β-amino-α-keto esters
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A method for the asymmetric synthesis of enantioenriched anti-α-hydroxy-β-amino acid derivatives by enantioconvergent reduction of the corresponding racemic α-keto esters is presented. The requisite α-keto esters are prepared via Mannich addition of ethyl
- Goodman, C. Guy,Do, Dung T.,Johnson, Jeffrey S.
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p. 2446 - 2449
(2013/06/27)
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- Highly efficient catalytic enantioselective mannich reaction of malonates with N-tert-butoxycarbonyl imines by using Yb(OTf)3/pybox catalysts at room temperature
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Go Mannich! A highly efficient and enantioselective method for the direct asymmetric reaction of dibenzyl malonate with N-tert-butoxycarbonyl aldimines in the presence of Yb(OTf)3 and iPr-pybox complexes is described (see scheme; pybox=pyridine
- Karimi, Babak,Jafari, Ehsan,Enders, Dieter
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supporting information
p. 10142 - 10145
(2013/09/02)
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- The homo-PADAM protocol: Stereoselective and operationally simple synthesis of α-oxo- or α-hydroxy-γ-acylaminoamides and chromanes
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A straightforward and fully stereoselective synthesis of a new class of peptidomimetics, that is α-oxo-γ-acylaminoamides, was achieved starting from various benzaldehydes by a sequence of 1) an asymmetric organocatalytic Mannich reaction, 2) a Passerini multicomponent reaction, 3) an amine deprotection-acyl migration protocol, and 4) a final oxidation. The whole sequence can be performed without purification of the intermediates and represents the first example of a homo-Passerini-amine deprotection-acyl migration (PADAM) strategy. Highly stereoselective reduction of the α-oxo-γ-acylaminoamides afforded α-hydroxy-γ- acylaminoamides as well. In some cases both diastereomers were obtained by simply changing the reducing agent. Finally, starting from protected salicylaldehyde, the same sequence, followed by a Mitsunobu cyclization, afforded highly substituted chromanes. Copyright
- Morana, Fabio,Basso, Andrea,Riva, Renata,Rocca, Valeria,Banfi, Luca
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p. 4563 - 4569
(2013/04/24)
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- Diastereo- and enantioselective Pd(II)-catalyzed additions of 2-alkylazaarenes to N -boc imines and nitroalkenes
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A chiral Pd(II)-bis(oxazoline) complex was found to be highly effective in promoting the first direct diastereo- and enantioselective addition of alkylazaarenes to N-Boc aldimines and nitroalkenes under mild conditions. Deprotection of Boc-protected products proceeded readily to provide amines in high yields.
- Best, Daniel,Kujawa, Szymon,Lam, Hon Wai
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p. 18193 - 18196
(2013/01/15)
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- Catalytic asymmetric synthesis of trisubstituted aziridines
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A method is described which provides for the direct asymmetric catalytic synthesis of trisubstituted aziridines from imines and diazo compounds. While unactivated imines were not reactive to α-diazo carbonyl compounds in which the diazo carbon was disubstituted, N-Boc imines react with both α-diazo esters and α-diazo-N-acyloxazolidinones to give trisubstituted aziridines with excellent diastereo- and enantioselectivities.
- Huang, Li,Wulff, William D.
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p. 8892 - 8895
(2011/08/04)
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- Rhodium(III)-catalyzed arylation of Boc-imines via C-H bond functionalization
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The first rhodium-catalyzed arylation of imines proceeding via C-H bond functionalization is reported. Use of a non-coordinating halide abstractor is important to obtain reactivity. Aryl-branched N-Boc-amines are formed, and a wide range of functionality is compatible with the reaction.
- Tsai, Andy S.,Tauchert, Michael E.,Bergman, Robert G.,Ellman, Jonathan A.
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supporting information; experimental part
p. 1248 - 1250
(2011/04/16)
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- Highly enantioselective titanium-catalyzed cyanation of imines at room temperature
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(Figure presented) A highly active and enantioselective titanium-catalyzed cyanatlon of imines at room temperature Is described. The catalyst used Is a partially hydrolyzed titanium alkoxide (PHTA) precatalyst together with a readily available N-salicyl-β-aminoalcohol ligand. Up to 98% ee was obtained with quantitative yields In 15 min of reaction time using 5 mol % of the catalyst. Various N-protecting groups such as benzyl, benzhydryl, Boc, and PMP are tolerated.
- Seayad, Abdul Majeed,Ramalingam, Balamurugan,Yoshinaga, Kazuhiko,Nagata, Takushi,Chai, Christina L. L.
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supporting information; experimental part
p. 264 - 267
(2010/03/24)
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- Heterobimetallic transition metal/rare earth metal bifunctional catalysis: A Cu/Sm/schiff base complex for Syn -selective catalytic asymmetric nitro-mannich reaction
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The full details of a catalytic asymmetric syn-selective nitro-Mannich reaction promoted by heterobimetallic Cu/Sm/dinucleating Schiff base complexes are described, demonstrating the effectiveness of the heterobimetallic transition metal/rare earth metal bifunctional catalysis. The first-generation system prepared from Cu(OAc)2/Sm(O-iPr)3/Schiff base 1a = 1:1:1 with an achiral phenol additive was partially successful for achieving the syn-selective catalytic asymmetric nitro-Mannich reaction. The substrate scope and limitations of the first-generation system remained problematic. After mechanistic studies on the catalyst prepared from Sm(O-iPr)3, we reoptimized the catalyst preparation method, and a catalyst derived from Sm 5O(O-iPr)13 showed broader substrate generality as well as higher reactivity and stereoselectivity compared to Sm(O-iPr)3. The optimal system with Sm5O(O-iPr)13 was applicable to various aromatic, heteroaromatic, and isomerizable aliphatic N-Boc imines, giving products in 66-99% ee and syn/anti = >20:1-13:1. Catalytic asymmetric synthesis of nemonapride is also demonstrated using the catalyst derived from Sm5O(O-iPr)13.
- Handa, Shinya,Gnanadesikan, Vijay,Matsunaga, Shigeki,Shibasaki, Masakatsu
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supporting information; experimental part
p. 4925 - 4934
(2010/06/18)
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- A novel bis-thiourea organocatalyst for the asymmetric aza-Henry reaction
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A novel bis-thiourea/2,2′-diaminobinaphthalene (BINAM)-based catalyst for the asymmetric aza-Henry reaction has been developed. This catalyst promotes the reaction of N-Boc imines with nitroalkanes to afford β-nitroamines with good yields and high enantioselectivities. This catalyst has the advantage that it can be prepared in a single step from commercially available materials. A model is proposed for the catalyst action where both components of the reaction are activated simultaneously by hydrogen bonding. Regardless of the mechanism, the success of the present catalyst demonstrates the potential of bis-thioureas as an interesting class of relatively unexplored catalysts.
- Rampalakos, Constantinos,Wulff, William D.
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supporting information; experimental part
p. 1785 - 1790
(2009/08/07)
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- Enantioselective aza-Henry reactions assisted by ZnII and N-methylephedrine
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(Chemical Equation Presented) Hooray aza-Henry! A combination of zinc triflate, an amine base, and (-)-N-methylephedrine (NME), which can be easily recovered and reused, leads to high enantioselectivities in the aza-Henry reaction of N-Boc-protected aldimines and nitromethane (see scheme; Boc = tert-butyloxycarbonyl).
- Palomo, Claudio,Oiarbide, Mikel,Halder, Rajkumar,Laso, Antonio,Lopez, Rosa
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p. 117 - 120
(2007/10/03)
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- Asymmetric mannich reactions with α-silylated trimethylsilyl enol ethers and N-alkoxycarbonyl imines
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The Mannich reaction of enantiomerically pure α-dimethylthexylsilylated trimethylsilyl enol ether (Z,S)-2 with titanium complexes of N-alkoxycarbonyl imines afforded α′-silylated αβ-disubstituted β-amino ketones (S,R,S)-4a-e in good to excellent yields (70-92percent) and diastereomeric excesses (de ≥ 96percent). Removal of the directing silyl group gave N-protected and anti-configured β-amino ketones (R,S)-5a-e in excellent yields (90-95percent) and stereoselectivities (de, ee ≥ 96percent- > 98percent).
- Enders, Dieter,Oberbo?rsch, Stefan
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p. 471 - 473
(2007/10/03)
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