Enantioselective nitroaldol (Henry) reaction using copper(<scp>ii</scp>) complexes of (−)-sparteine

Maheswaran, H.; Prasanth, K. Leon; Krishna, G. Gopi; Ravikumar, K.; Sridhar, B.; Kantam, M. Lakshmi

doi:10.1039/b610203d

Cited by 118 publications

(41 citation statements)

References 37 publications

(2 reference statements)

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“…With alkyl-substituted keto esters (Table 8, entries 12-16), we obtained similar results using either linear (entries [12][13][14] or branched groups (entries 15 and 16). The reaction afforded the expected products in good to excellent yields and with ee values in the range of 78-82% ee.…”

Section: Enantioselective Henry Reaction With A-keto Esterssupporting

confidence: 80%

Development of New N,N-Ligands for the Enantioselective Copper(II)-Catalyzed Henry Reaction

Blay¹,

Hernández‐Olmos²,

Pedro³

2011

Synlett

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This account shows our efforts towards the development of new N,N-ligands and their application in the asymmetric Henry reaction. Iminopyridine ligands were prepared by the condensation of chiral monoterpene ketones and pyridinylalkylamines. The complexes of these ligands with copper(II) ions catalyzed the enantioselective addition of nitromethane to aldehydes with generally high yields and moderate enantioselectivities. The same reaction with other nitroalkanes gave racemic products. Stereoselective reduction of the imino group allowed us to obtain new aminopyridine ligands. The new ligands were shown to be more efficient, and they catalyzed the addition of nitromethane and also larger nitroalkanes to aldehydes to give the corresponding products in generally very high yields and excellent enantiomeric excesses. We have used this aminopyridine catalytic system in the first catalytic enantioselective Henry reactions with bromo(nitro)methane and methyl 4-nitrobutanoate. The reaction involving the latter substrate gave multifunctional chiral building blocks that were transformed into g-lactams and d-lactones. The application of the reaction to the synthesis of known amino(aryl)ethanol pharmaceuticals is also reported. Iminopyridine ligands, however, were more efficient in the addition of nitromethane to a-keto esters.

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Section: Enantioselective Henry Reaction With A-keto Esterssupporting

confidence: 80%

Development of New N,N-Ligands for the Enantioselective Copper(II)-Catalyzed Henry Reaction

Blay¹,

Hernández‐Olmos²,

Pedro³

2011

Synlett

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“…Nevertheless, other metals such as Zn, [8] Co, [9] Cr, [10] Pd, [11] and rare metals [5,11,12] have also been examined with variable success. The majority of ligands developed, for example, bisoxazolines, [13] bisoxazolidines, [14] diamines, [15] (-)-sparteine, [16] sulfonyldiamines, [7c] sulfonimidamides, [7a] aminopyridines, [17] tetrahydrosalens, [18] and N,NЈ-dioxides, [7b] are nitrogen-based with a variety of structural features that modulate their reactivity and enantioselectivity. Limitations such as ligand complexity, low substrate scope, high catalyst loading, and requirement for strict reaction conditions mandate the development of more robust and efficient ligands.…”

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confidence: 99%

Efficient Asymmetric Copper(I)‐Catalyzed Henry Reaction Using Chiral N‐Alkyl‐C₁‐tetrahydro‐1,1′‐bisisoquinolines

Ji¹,

Gao²,

Judeh³

2011

Eur J Org Chem

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A series of closely related chiral N‐alkyl‐C1‐tetrahydro‐1,1′‐bisisoquinoline ligands only differing in the steric bulk of the alkyl groups has been examined in the asymmetric Henry reaction. A complex derived from the (R)‐N‐methyl‐1′,2′,3′,4′‐tetrahydro‐1,1′‐bisisoquinoline and copper(I) chloride proved to be a very efficient catalyst system that can promote the reaction of a wide range of aromatic and aliphatic aldehydes to give the expected nitroalcohol products in high yields (up to 99 %), excellent enantioselectivities (up to 94 % ee), and moderate diastereoselectivities (up to 1.6:1). This catalyst system is very general, requires no additives for activation, and is also simple in operation because no special precautions are taken to exclude moisture or air from the reaction flask.

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“…Initially organolithium compounds were applied in asymmetric deprotonation, substitution and addition reactions [21,22]. Later chiral complexes of sparteine with other metal ions were used, such as complexes of magnesium [23], tin [24], titanium [25,26], copper [27,28], manganese [29], and palladium [30,31].…”

Section: Resultsmentioning

confidence: 99%

Enantioselective 1,3‐dipolar cycloaddition reactions using complexes of (−)‐sparteine

Gucma

Golebiewski

2008

Journal of Heterocyclic Chem

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Enantioselective nitroaldol (Henry) reaction using copper(ii) complexes of (−)-sparteine

Abstract: The dichloro[(-)-sparteine-N,N']copper(II) complex provides Henry adducts with high enantioselectivities (73-97% ee) in Henry reaction between nitromethane and various aldehydes.

Cited by 118 publications

References 37 publications

Development of New N,N-Ligands for the Enantioselective Copper(II)-Catalyzed Henry Reaction

Development of New N,N-Ligands for the Enantioselective Copper(II)-Catalyzed Henry Reaction

Efficient Asymmetric Copper(I)‐Catalyzed Henry Reaction Using Chiral N‐Alkyl‐C₁‐tetrahydro‐1,1′‐bisisoquinolines

Enantioselective 1,3‐dipolar cycloaddition reactions using complexes of (−)‐sparteine

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Enantioselective nitroaldol (Henry) reaction using copper(ii) complexes of (−)-sparteine

Abstract: The dichloro[(-)-sparteine-N,N']copper(II) complex provides Henry adducts with high enantioselectivities (73-97% ee) in Henry reaction between nitromethane and various aldehydes.

Cited by 118 publications

References 37 publications

Development of New N,N-Ligands for the Enantioselective Copper(II)-Catalyzed Henry Reaction

Development of New N,N-Ligands for the Enantioselective Copper(II)-Catalyzed Henry Reaction

Efficient Asymmetric Copper(I)‐Catalyzed Henry Reaction Using Chiral N‐Alkyl‐C1‐tetrahydro‐1,1′‐bisisoquinolines

Enantioselective 1,3‐dipolar cycloaddition reactions using complexes of (−)‐sparteine

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Efficient Asymmetric Copper(I)‐Catalyzed Henry Reaction Using Chiral N‐Alkyl‐C₁‐tetrahydro‐1,1′‐bisisoquinolines