Nitrogen-Containing Ligands for Asymmetric Homogeneous and Heterogeneous Catalysis

Fache, Fabienne; Schulz, Emmanuelle; Tommasino, and M. Lorraine; Lemaire, Marc

doi:10.1021/cr9902897

Cited by 888 publications

(360 citation statements)

References 619 publications

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“…However, it was both encouraging and disappointing to find that although the reactivity was indeed enhanced significantly, no enantioselectivity was observed with most of these chiral catalysts. On the other hand, numerous enantioselective addition reactions with chiral copperbis(oxazoline) box complexes have been described during the past two decades (59)(60)(61). Therefore, we decided to try chiral bis(oxazolinyl) ligands in our reaction and found that the desired enantioselective addition product was formed with a low enantioselectivity by using bidentate box 1 and 2 with CuBr complex as catalysts in water (Fig.…”

Section: Resultsmentioning

confidence: 99%

Cu(I)-catalyzed direct addition and asymmetric addition of terminal alkynes to imines

Wei

Mague²,

Li³

2004

Proc. Natl. Acad. Sci. U.S.A.

201

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A Cu(I)-catalyzed direct addition of alkynes to imines was developed. The process is simple and provides a diverse range of propargylamines in high enantiomeric excess and good yield both in water and in toluene. The absolute configuration of such addition products has been determined by x-ray crystallography.A s in the case for the addition reaction of carbanions to the carbonyl group of aldehydes and ketones (1-4), the addition of organometallic reagents to the CAN bonds of imines or imine derivatives is an important reaction in organic synthesis (5-9). The carbon-carbon bond-forming method, which uses alkynes as a carbon nucleophile source, is a useful method in synthesis (10, 11). The resulting alkynyl amine derivatives can undergo further transformations and are versatile synthetic tools (12)(13)(14). However, the reactive alkynilides are usually prepared from terminal alkyne by using highly reactive organometallic reagents such as BuLi (15,16), EtMgBr (17,18), or LDA (19,20) in a separate step, and many metal alkynilides are not easy to handle because the reaction must be carried out under anhydrous solvent, inert atmosphere, and low temperature conditions. Therefore, the development of a method for the direct alkynylation of imines that does not use a stoichiometric amount of highly reactive organometallic reagent and can be performed under mild conditions would be highly desirable. Additionally, there has been greater interest in recent years in developing environmentally friendly reactions in aqueous media (21,22).Optically active propargyl amines are important synthetic intermediates for the synthesis of various nitrogen compounds and are components of bioactive compounds or natural products (23-25). Recently, great efforts have been made to develop the methodology for generating propargylamines (26-33). Some direct alkynylations of carbonyl compounds with terminal alkynes have been reported (34-37). Miura (38) has reported the addition of acetylene to nitrones in the presence of a catalytic amount of CuI with K 2 CO 3 as the base and phosphine-and nitrogen-containing compounds as the ligands in N,NЈ-dimethylformamide at 80°C under nitrogen, to give a (2 ϩ 2) coupling product along with a redox product, alkynyl imine. Carreira (39-41) has used a Zn(II)-catalyzed process in CH 2 Cl 2 for the addition of terminal alkynes to nitrones to form propargyl N-hydroxyamine adducts and recently reported (42) the addition of terminal alkynes to imines by an iridium catalyst in toluene or under neat conditions. Ishii (43) reported an ''unexpected'' case of the addition of alkyne to imine by an Ir(I) catalyst. Jiang (44) has reported the addition of terminal alkynes to imines by using ZnCl 2 and Et 3 N as catalysts and TMSCl as the Lewis acid for the activation of imines. Methods for the catalytic preparation of optically active propargyl amines are still limited (10-14, 30, 31).One of our ongoing interests is in the development of transition metal-catalyzed carbon-carbon bond formation in water (45-48). We have rec...

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Section: Resultsmentioning

confidence: 99%

Cu(I)-catalyzed direct addition and asymmetric addition of terminal alkynes to imines

Wei

Mague²,

Li³

2004

Proc. Natl. Acad. Sci. U.S.A.

201

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“…The formation of the Schiff base, however, is not restricted to salicylaldehyde derivatives. It proceeds as well with other aromatic aldehydes [2,3]. Previously 2-(2-propynyloxy)benzaldehyde has been used as a starting material in cycloaddition reactions [4].…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of 2-(2-propynyloxy)benzaldehyde, C10H8O2

Werz

Balalaie

Röminger

et al. 2006

Zeitschrift Für Kristallographie - New Crystal Structures

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“…The formation of the Schiff base, however, is not restricted to salicylaldehyde derivatives. It proceeds as well with other aromatic aldehydes [7,8]. Thus we envisioned to use 2-[6-(2-formylphenoxy)-2,4-hexadiynyloxy]benzaldehyde as starting material for the synthesis of some new Schiff bases.…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of 2-[6-(2-formylphenoxy)-2,4-hexadiynyloxy]- benzaldehyde, C20H14O4

Werz

Balalaie

Rominger

et al. 2006

Zeitschrift Für Kristallographie - New Crystal Structures

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Nitrogen-Containing Ligands for Asymmetric Homogeneous and Heterogeneous Catalysis

Cited by 888 publications

References 619 publications

Cu(I)-catalyzed direct addition and asymmetric addition of terminal alkynes to imines

Cu(I)-catalyzed direct addition and asymmetric addition of terminal alkynes to imines

Crystal structure of 2-(2-propynyloxy)benzaldehyde, C10H8O2

Crystal structure of 2-[6-(2-formylphenoxy)-2,4-hexadiynyloxy]- benzaldehyde, C20H14O4

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