- Chiral Bronsted Acids Catalyze Asymmetric Additions to Substrates that Are Already Protonated: Highly Enantioselective Disulfonimide-Catalyzed Hantzsch Ester Reductions of NH-Imine Hydrochloride Salts
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While imines are frequently used substrates in asymmetric Bronsted acid catalysis, their corresponding salts are generally considered unsuitable reaction partners. Such processes are challenging because they require the successful competition of a catalytic amount of a chiral anion with a stoichiometric amount of an achiral one. We now show that enantiopure disulfonimides enable the asymmetric reduction of N-H imine hydrochloride salts using Hantzsch esters as hydrogen source. Our scalable reaction delivers crystalline primary amine salts in great efficiency and enantioselectivity and the discovery suggests potential of this approach in other Bronsted acid catalyzed transformations of achiral iminium salts. Kinetic studies and acidity data suggest a bifunctional catalytic activation mode.
- Wakchaure, Vijay N.,Obradors, Carla,List, Benjamin
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supporting information
p. 1707 - 1712
(2020/08/28)
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- Reversal diastereoselectivity between the organomagnesium and organolithium reagents on Chiral N-tert-butylsulfinylaldimines for the preparation of chiral amines
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The asymmetric synthesis of both the enantiomer of chiral amines from the single chiral source of N-tert-butylsulfinylaldimines (3) by simply changing the organometallic reagents through diastereoselective addition. An efficient enantioselective synthesis of chiral amines including (S)-3-methyl-1-(2- piperidin-1-yl-phenyl)butyl amine (6a), a key intermediate to prepare antidiabetic drug repaglinide (1), is reported.
- Rajendiran, Chinnapillai,Nagarajan, Periyandi,Naidu,Dubey
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p. 2936 - 2942
(2014/11/08)
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- Rhodium-catalyzed asymmetric hydrogenation of unprotected NH imines assisted by a thiourea
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Asymmetric hydrogenation of unprotected NH imines catalyzed by rhodium/bis(phosphine)-thiourea provided chiral amines with up to 97% yield and 95% ee. 1HNMR studies, coupled with control experiments, implied that catalytic chloride-bound intermediates were involved in the mechanism through a dual hydrogen-bonding interaction. Deuteration experiments proved that the hydrogenation proceeded through a pathway consistent with an imine.
- Zhao, Qingyang,Wen, Jialin,Tan, Renchang,Huang, Kexuan,Metola, Pedro,Wang, Rui,Anslyn, Eric V.,Zhang, Xumu
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supporting information
p. 8467 - 8470
(2014/08/18)
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- One-pot synthesis of chiral nonracemic amines
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One-pot five-component reactions of oxathiazolidine-S-oxides with mesitylmagnesium bromide, lithium bis(trimethylsilyl)amide, aldehydes and Grignard reagents afford chiral nonracemic amines or sulfinamides in good yields and high stereoselectivities.
- Roe, Caroline,Hobbs, Heather,Stockman, Robert A.
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experimental part
p. 9452 - 9459
(2012/01/06)
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- Stereoselective synthesis of α-arylalkylamines by glycosylation-induced asymmetric addition of organometallic compounds to imines
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Activation of imines of aromatic aldehydes by N-glycosylation with O-pivaloyl-galactopyranosyl bromide (pivalobromogalactose) and subsequent addition of organotin, organolithium, Grignard, or organozinc reagents afforded α-arylalkylamines with moderate to
- Allef, Petra,Kunz, Horst
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experimental part
p. 646 - 652
(2009/12/26)
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- Enantioselective hydrogenation of N-H imines
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(Figure Presented) N-H ketoimines 3a-3v are readily prepared in high yield via organometallic addition to nitriles and isolated as corresponding bench-stable hydrochloride salts. Homogeneous asymmetric hydrogenation of unprotected N-H ketoimines 3a-3v usi
- Hou, Guohua,Gosselin, Francis,Li, Wei,McWilliams, J. Christopher,Sun, Yongkui,Weisel, Mark,O'Shea, Paul D.,Chen, Cheng-Yi,Davies, Ian W.,Zhang, Xumu
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supporting information; experimental part
p. 9882 - 9883
(2009/12/06)
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- General one-pot method for the preparation of N-tert-butanesulfinylamine diastereomer mixtures as standards for stereoselectivity determinations
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The one-pot preparation of N-sulfinylamine diastereomers proceeds in excellent yields (84-98%) for a diverse set of N-sulfinyl imine addition products. The method is operationally simple and extractive isolation provides analytically pure mixtures of dias
- Brak, Katrien,Barrett, Kimberly T.,Ellman, Jonathan A.
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supporting information; experimental part
p. 3606 - 3608
(2009/09/06)
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- Reversal of diastereofacial selectivity in hydride reductions of N-tert-butanesulfinyl imines
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A variety of N-tert-butanesulfinyl imines were reduced with NaBH 4 in THF containing 2% water to provide the corresponding secondary sulfinamides in high yield and diastereoselectivity. By using the same sulfinyl imine starting materials and changing the reductant to L-Selectride, the stereoselectivity could be efficiently reversed to afford the opposite product diastereomer in high yield and selectivity.
- Colyer, John T.,Andersen, Neil G.,Tedrow, Jason S.,Soukup, Troy S.,Faul, Margaret M.
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p. 6859 - 6862
(2007/10/03)
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- Multicomponent one-pot procedure for the synthesis of free α-chiral amines from aldehydes
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The synthesis of free a-chiral amines by a one-pot multi-component procedure from commercially available starting materials is described. This enantioselective reaction involves a catalytic asymmetric addition of dialkylzinc reagents to N-diphenylphosphin
- Cote, Alexandre,Charette, Andre B.
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p. 10864 - 10867
(2007/10/03)
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- Catalytic enantioselective addition of dialkylzinc to N-diphenylphosphinoylimines. A practical synthesis of α-chiral amines
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The enantioselective addition of dialkylzinc reagents to N-diphenylphosphinoylimines derived from aryl-, furyl-, and cyclopropylaldehydes is efficiently catalyzed by a copper(II) triflate/(R,R)-MeDUPHOS complex. The yields are high (51-98%), and the enant
- Boezio, Alessandro A.,Charette, Andre B.
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p. 1692 - 1693
(2007/10/03)
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- Asymmetric synthesis of chiral amines by highly diastereoselective 1,2- additions of organometallic reagents to N-tert-butanesulfinyl imines
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High yielding and highly diastereoselective methods for 1,2-additions of organometallic reagents to N-tert-butanesulfinyl aldimines (2) and N-tert- butanesulfinyl kerimines (3) are described. The additions of alkyl, aryl, alkenyl, and allyl carbanions to a diverse set of imines with different steric and electronic properties are demonstrated. Acidic methanolysis of the sulfinamide products (4 and 6) delivers highly enantioenriched α-branched and α,α-dibranched amines. Since a broad range of sulfinyl imines are easily accessible from aldehydes and ketones, a wide variety of enantioentriched amines may be prepared.
- Cogan, Derek A.,Liu, Guangcheng,Ellman, Jonathan
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p. 8883 - 8904
(2007/10/03)
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- Chiral quaternary benzophenone hydrazonium salt derivatives; efficient chiral catalysts for the enantioselective phase-transfer alkylation of imines. Application to synthesis of chiral primary amines
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(2S)-1-Methyl-1-[N-(diphenylmethylene)-2-hydroxymethylpyrrolidine hydrazonium iodide I-a has been designed to catalyse the enantioselective phase-transfer alkylation of N-(diphenylmethylene) benzenemethanamine II. Although the weak acidic character of the latter, alkylations have been performed within reasonable reaction times. Optically active primary amines III a-e have been prepared in good chemical yields and up to 94% e.e. using 2-5 mol-% of the chiral catalyst only.
- Jamal Eddine,Cherqaoui
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p. 1225 - 1228
(2007/10/02)
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