Rhodium-catalyzed Reformatsky-type reaction for asymmetric synthesis of difluoro-β-lactams using menthyl group as a chiral auxiliary

Tarui, Atsushi; Ozaki, Daiki; Nakajima, Naoko; Yokota, Yuto; Sokeirik, Yasser S.; Sato, Kazuyuki; Omote, Masaaki; Kumadaki, Itsumaro; Andõ, Akira

doi:10.1016/j.tetlet.2008.04.101

Cited by 46 publications

(24 citation statements)

References 39 publications

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“…1 H NMR (300 MHz, CDCl 3 ): 7.59 (d,2H,J = 7.3 Hz),8H),6.80 (m,2H) 1,136.1,132.7 (d,J = 1.2 Hz),128.7,128.6,128.4,128.3,127.0,126.9 (t,J = 1.9 Hz),126.8 (d,J = 2.5 Hz),114.4 (t,J = 262.8 Hz),77.9 (t,J = 24.0 Hz),63.3,13.8. 1 H NMR (300 MHz, CDCl 3 ): 7.59 (d,2H,J = 7.3 Hz),8H),6.80 (m,2H) 1,136.1,132.7 (d,J = 1.2 Hz),128.7,128.6,128.4,128.3,127.0,126.9 (t,J = 1.9 Hz),126.8 (d,J = 2.5 Hz),114.4 (t,J = 262.8 Hz),77.9 (t,J = 24.0 Hz),63.3,13.8.…”

Section: Methodsmentioning

confidence: 99%

Indium-Promoted Reformatsky Reaction: A Straightforward Access to β-Amino and β-Hydroxy α,α-Difluoro Carbonyl Compounds

2012

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A versatile and practical methodology to access β-amino and β-hydroxy α,α-difluoro carbonyl compounds using indium metal is described. This methodology has been successfully applied to a broad range of substrates including aldehydes, ketones, and imines, affording the corresponding and highly valuable gem-difluoro esters. The wide substrate scope highlights the chemoselectivity of the process.

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Section: Methodsmentioning

confidence: 99%

Indium-Promoted Reformatsky Reaction: A Straightforward Access to β-Amino and β-Hydroxy α,α-Difluoro Carbonyl Compounds

2012

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“…Some recent reactions have been mediated by zinc, 65 rhodium, 66 indium, 67 and diethylzinc. 68 Boyer and coworkers have studied the parameters influencing the selective synthesis of 2-azetidinones 96 or β-amino esters 97 during the Reformatsky reaction of ethyl bromodifluoroacetate 95 with imines 11.…”

Section: Ester-enolate Cycloadditionsmentioning

confidence: 99%

“…Tarui and coworkers have reported an asymmetric synthesis of (S)-3,3-difluoro-2-azetidinones 102 in moderate to good yields with high diastereoselectivity together with a β-amino ester 103 by the Reformatsky type reaction of (-)-menthyl bromodifluoroacetate 100 with imines 101 in the presence of RhCl(PPh 3 ) 3, followed by spontaneous elimination of the chiral auxiliary (Scheme 30). 66 Among the imines of aromatic aldehydes, those bearing electrondonating groups offered higher enantioselectivity (ee 92-94%) than those bearing electronwithdrawing groups (ee 80-87%). Isobutyraldehyde imine in this reaction, however, afforded a racemate.…”

Section: Ester-enolate Cycloadditionsmentioning

confidence: 99%

Advances in synthesis of monocyclic beta-lactams

Singh¹,

Sudheesh²

2014

Arkivoc

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Recent years have witnessed significant advancement in cycloaddition and cyclization strategies for the synthesis of monocyclic β-lactams. Cycloadditions include the Staudinger's keteneimine cycloaddtions and related reaction. Cyclization reactions are reported to furnish β-lactams through N 1 -C 2 , N 1 -C 4 and C 3 -C 4 bond formations employing substrates like β-amino esters, β-amino alcohols, β-hydroxamate esters, and α-amino diazocarbonyls, etc. Some other strategies are silyl carbonylation reactions, ring-enlargement of aziridines, cleavage of one ring of a bicyclic β-lactam, and functional group transformations on the β-lactam rings. Recently, some multi-component reactions have also been designed. This article reviews the advances made in synthetic approaches to monocyclic β-lactams during last five years.

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“…This reaction of 16A could be applied to aromatic and aliphatic imines, giving the desired products with high ee (Scheme 7). [17] The absolute configuration of 3h was determined as shown in Scheme 8: (i) 3h and 13a of known configuration 13a were transformed to the identical N-deprotected difluoro-b-lactams (19a) respectively; (ii) by comparison of retention times of these products on chiral HPLC, the absolute configuration of 3h was found to be same as that of 13a, namely the (4S) configuration.…”

Section: Using Bromodifluoroacetate From Chiral Alcoholsmentioning

confidence: 99%

Stereoselective Synthesis of α‐Fluorinated Amino Acid Derivatives

et al. 2010

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This account concentrates on our new methodologies for the synthesis of fluorine analogues of amino acids and their derivatives using the Reformatsky-type reactions of ethyl bromodifluoroacetate and ethyl dibromofluoroacetate with imines promoted by the Wilkinson catalyst. First, we present the rhodium-catalyzed Reformatsky-type reaction of ethyl bromodifluoroacetate with imines using diethylzinc for the chemoselective synthesis of a,a-difluoro-b-lactams and non-cyclized products, 3-alkylamino-2,2-difluorocarboxylates. This reaction was expanded to the asymmetric synthesis of difluoro-b-lactams using two types of chiral auxiliaries. To develop another methodology for the synthesis of mono-A C H T U N G T R E N N U N G fluoro analogues of amino acids and their derivatives, we investigated the reaction of ethyl dibromofluoroacetate with imines using diethylzinc, and found that this Reformatsky-type reaction proceeded without a rhodium catalyst in diethyl ether to give syn-a-bromo-a-fluoro-b-lactams stereoselectively. Interestingly, by changing the solvent to acetonitrile, the Reformatsky-type aza-Darzens products, syn-2-fluoroaziridine-2-carboxylates, were obtained chemoand stereoselectively.

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Rhodium-catalyzed Reformatsky-type reaction for asymmetric synthesis of difluoro-β-lactams using menthyl group as a chiral auxiliary

Cited by 46 publications

References 39 publications

Indium-Promoted Reformatsky Reaction: A Straightforward Access to β-Amino and β-Hydroxy α,α-Difluoro Carbonyl Compounds

Indium-Promoted Reformatsky Reaction: A Straightforward Access to β-Amino and β-Hydroxy α,α-Difluoro Carbonyl Compounds

Advances in synthesis of monocyclic beta-lactams

Stereoselective Synthesis of α‐Fluorinated Amino Acid Derivatives

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