The Catalytic Asymmetric Mannich-Type Reactions in Aqueous Media

Kobayashi, Shū; Hamada, Takeo; Manabe, Kei

doi:10.1021/ja026094p

Cited by 224 publications

(119 citation statements)

References 30 publications

(18 reference statements)

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“…Under bulk solution-phase conditions, this multi-component condensation of a non-enolizable aldehyde, primary or secondary amine, and an enolizable carbonyl compound (i.e., carbonyl compound having one or more α-hydrogen atoms) affords β-amino carbonyl products. Often, the desired Mannich product is generated by indirect procedures in which either the enolate or the imine (i.e., the Schiff base) is preformed [23][24][25]. Direct one-pot Mannich reactions have been reported, however, catalysts and long reaction times are typically needed [26,27] (Figure 2b) do not reflect the relative amounts present in the collected material.…”

Section: Resultsmentioning

confidence: 99%

Accelerated C–N Bond Formation in Dropcast Thin Films on Ambient Surfaces

Badu‐Tawiah

Campbell

Cooks

2012

J. Am. Soc. Mass Spectrom.

104

109

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The aza-Michael addition and the Mannich condensation occur in thin films deposited on ambient surfaces. The reagents for both C-N bond formation reactions were transferred onto the surface by drop-casting using a micropipette. The surface reactions were found to be much more efficient than the corresponding bulk solution-phase reactions performed on the same scale in the same acetonitrile solvent. The increase in rate of product formation in the thin film is attributed to solvent evaporation in the open air which results in reagent concentration and produces rate acceleration similar to that seen in evaporating droplets in desorption electrospray ionization. This thin film procedure has potential for the rapid synthesis of reaction products on a small scale, as well as allowing rapid derivatization of analytes to produce forms that are easily ionized by electrospray ionization. Analysis of the derivatized sample directly from the reaction surface through the use of desorption electrospray ionization is also demonstrated.

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Section: Resultsmentioning

confidence: 99%

Accelerated C–N Bond Formation in Dropcast Thin Films on Ambient Surfaces

Badu‐Tawiah

Campbell

Cooks

2012

J. Am. Soc. Mass Spectrom.

104

109

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“…Stilbenediamine containing metal complexes of copper, nickel and zinc have been catching attention due to their catalytic activity in asymmetric syntheses [2][3][4][5][6][7][8][9]. Recently achiral copper catalyst having dibenzoylstilbene as its ligand has been developed to achieve enantioselective Mannich-type reactions of Nacylimino esters with, for example, alkyl vinyl ethers to afford the corresponding N-acylated amino acid derivatives [7].…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of ethanolato-dibenzoylmethanato-(R,R-dibenzoylstilbenediamine)-nitratonickel(II), Ni(C2H5OH)(C15H11O2)(C28H26N2)(NO3)

Miyamoto¹,

Yajima²,

Horn³

et al. 2010

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of materialThe title compound was prepared by adding 0.393 gofdibenzoylstilbenediamine (dbstien) obtained according to the published method [1] to 0.291 gofNi(NO 3 ) 2 · 6H 2 Odissolved in 10 ml of ethanol followed by the addition of 0.224 gofdibenzoylmethane and 0.07 go fK OH, and stirred for 60 minutes. The resulting bluish-green solution was filtered, allowed to stand. Green crystals suitable for X-ray diffraction experiments were obtained by slow vapour diffusion of diethyl ether into the ethanol solution. Experimental detailsThe hydrogen atoms bound to carbon atoms were fixed at calculated positions with d(C-H) =0.97 Å, d(C=C-H) =1.08 Å.The hydrogen bound to O6 was not located in the difference Fourier map due to the probable disorder over two sites. DiscussionStilbenediamine containing metal complexes of copper, nickel and zinc have been catching attention due to their catalytic activity in asymmetric syntheses [2][3][4][5][6][7][8][9]. Recently achiral copper catalyst having dibenzoylstilbene as its ligand has been developed to achieve enantioselective Mannich-type reactions of Nacylimino esters with, for example, alkyl vinyl ethers to afford the corresponding N-acylated amino acid derivatives [7]. To date, only af ew structures of these complexes have been reported, hence our interest to isolate, crystallize and to determine the molecular structure of the nickel complex presented here. The crystal structure consists of asymmetric units containing one Ni complex, [Ni(C 2H6O)(C15H11O2)(C28H28N2)(NO3)]. The central nickel atom has as lightly distorted octahedral coordination, with the angles around nickel ranging from 81.9(2)°to 103.1(2)°,and 172.8(2)°to 177.1(2)°,respectively. The average Ni-Ndistance (Ni-N2, Ni-N3) is 2.091(5) Å,which is in the normal bond range for an octahedral Ni complex. The respective Ni-O dbm distances Ni-O4 and Ni-O5 are 1.976(4) Å and 2.033(4) Å which reflect the relative trans effect exhibited by N3 as opposed to O6 (ethanol), making the former distance shorter. The nitrate molecule coordinates Ni at the expected distance Ni-O1 of 2.179(4) Å.T he dibenzoylstilbene and dibenzoylmethanate (dbm) bidentate chelate planes are virtually perpendicular to each other. The atomic arrangement around atoms C16 and C17 reflects the R,R configuration of dibenzoylstilbene of the overall absolute molecular structure. Finally, the oxygen of the ethanol molecule locates at the normal distance of 2.083(4) Å from the nickel centre.

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“…List, 2002;2000;R.O. Duthaler, 2003), acetic acid (K. Mogilaiah, 2002), p-dodecylbenzenesulfonic acid (K. Manabe, 2001) and some Lewis acids (S. Kobayashi, 2002;P. Desai, 2000).…”

Section: Introductionmentioning

confidence: 99%