Application of chiral ligands: carbohydrates, nucleoside-lanthanides and other Lewis acid complexes to control regio- and stereoselectivity of the dipolar cycloaddition reactions of nitrile oxides and esters

Gucma, Mirosław; Golebiewski, W. Marek; Krawczyk, Maria

doi:10.1039/c4ra15975f

Cited by 14 publications

(9 citation statements)

References 46 publications

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“…Purification by column chromatography (hexanes/EtOAc, 10:1 v/v) afforded product 3l ; 83% (106 mg, 0.83 mmol) light yellow oil; 1 H NMR (400 MHz, CDCl 3 ) δ 5.60 (ddd, J = 13.5, 9.8, 7.4 Hz, 1H), 5.46 (dddd, J = 9.2, 8.4, 4.9, 3.4 Hz, 1H), 4.58 (dd, J = 6.9, 0.4 Hz, 2H), 2.12–2.04 (m, 2H), 2.01 (s, 3H), 0.95 (t, J = 7.5 Hz, 3H); 13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ 170.8, 136.8, 122.6, 60.2, 20.8, 20.7, 13.9. The 1 H and 13 C{ 1 H} NMR data were in accordance with those reported in the literature …”

Section: Methodssupporting

confidence: 89%

“…The 1 H and 13 C{ 1 H} NMR data were in accordance with those reported in the literature. 65 3-Phenylprop-2-ynyl Acetate (3m). Purification by column chromatography (hexanes/EtOAc, 10:1 v/v) afforded product 3m; 94% (164 mg, 0.94 mmol) light yellow oil; 1 H NMR (400 MHz, CDCl 3 ) δ 7.51−7.38 (m, 2H), 7.38−7.26 (m, 3H), 4.90 (s, 2H), 2.12 (s, 3H); 13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ 170.2, 131.8, 128.7, 128.2, 122.1, 86.4, 82.9, 52.8, 20.7.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Evaluation of gem-Diacetates as Alternative Reagents for Enzymatic Regio- and Stereoselective Acylation of Alcohols

et al. 2021

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Geminal diacetates have been used as sustainable acyl donors for enzymatic acylation of chiral and nonchiral alcohols. Especially, it was revealed that geminal diacetates showed higher reactivity than vinyl acetate for hydrolases that are sensitive to acetaldehyde. Under optimized conditions for enzymatic acylation, several synthetically relevant saturated and unsaturated acetates of various primary alcohols were obtained in very high yields up to 98% without E/Z isomerization of the double bond. Subsequently, the acyl donor was recreated from the resulting aldehyde and reused constantly in acylation. Therefore, the developed process is characterized by high atomic efficiency. Moreover, it was shown that acylation using geminal diacetates resulted in remarkable regioselectivity by discriminating among the primary and secondary hydroxyl groups in 1-phenyl-1,3-propanediol providing exclusively 3-acetoxy-1-phenyl-propan-1-ol in good yield. Further, enzymatic kinetic resolution (EKR) and chemoenzymatic dynamic kinetic resolution (DKR) protocols were developed using geminal diacetate as an acylating agent, resulting in chiral acetates in high yields up to 94% with enantiomeric excesses exceeding 99%.

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Section: Methodssupporting

confidence: 89%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Evaluation of gem-Diacetates as Alternative Reagents for Enzymatic Regio- and Stereoselective Acylation of Alcohols

et al. 2021

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“…The following comprehensive research study from Gucma and Gołębiewski came out in 2011 and concerned 1,3-DP cycloaddition between ArCNO and α,ß-unsaturated amides and esters. It was used to obtain chiral substituted isoxazolines— Scheme 197 [ 209 , 210 ]. These reactions were mediated by complexes of carbohydrates A and B alkaloids ((+)-cinchonine, (−)-cinchonidine, (−)-sparteine), R-BINOL with Yb(OTf) 3 , Yb(ClO 4 ) 3 , YbCl 3 , TiCl 4 , Mg(OTf) 2 , MgBr 2 , and CsF complexes without any auxiliaries.…”

Section: Syntheses Of Substituted 2-isoxazolines Via 13-dp Cycloaddit...mentioning

confidence: 99%

“…Unfortunately, attempts to decrease the amounts of catalytic systems from equimolar to catalytic quantities were effective only for R-BINOL-Yb(OTf) 3 and L4-Yb(OTf) 3 systems. In most cases, cycloaddition was not regioselective, but in many cases, it was highly enantioselective for both or one of the regioisomers [ 209 , 210 ].…”

Section: Syntheses Of Substituted 2-isoxazolines Via 13-dp Cycloaddit...mentioning

confidence: 99%

Nitrile Oxide, Alkenes, Dipolar Cycloaddition, Isomerization and Metathesis Involved in the Syntheses of 2-Isoxazolines

et al. 2023

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The involvement of 1,3-dipolar cycloaddition (1,3-DP), double bond migration, metathesis, and nitrile oxide (including in situ-generated nitrile oxide) as dipoles, together with the C=C bond containing dipolarophiles, in the syntheses of 2-isoxazolines is presented. Methods for synthesizing isoxazolines (other than 1,3-DP cycloaddition) were also presented briefly. Various methods of nitrile oxide preparation, especially in situ-generated procedures, are presented. Special attention was paid to the application of various combinations of 1,3-DP cycloaddition with double bond migration (DBM) and with alkene metathesis (AM) in the syntheses of trisubstituted isoxazolines. Allyl compounds of the type QCH2CH=CH2 (Q = ArO, ArS, Ar, and others) play the role of dipolarophile precursors in the combinations of DPC mentioned, DBM and AM. Mechanistic aspects of cycloadditions, i.e., concerted or stepwise reaction mechanism and their regio- and stereoselectivity are also discussed from experimental and theoretical points of view. Side reactions accompanying cycloaddition, especially nitrile oxide dimerization, are considered. 2-Isoxazoline applications in organic synthesis and their biological activity, broad utility in medicine, agriculture, and other fields were also raised. Some remaining challenges in the field of 1,3-DP cycloaddition in the syntheses of isoxazolines are finally discussed.

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“…The most significant results are depicted in Scheme 9 31. To the best of our knowledge only one example of lipase-catalyzed 1,3-DC of NOs has been reported 32. Thus, in the presence of immobilized lipase B from Candida antarctica, the reaction of 4-trifluoromethylbenzonitrile oxide 32 to crotonate 33 afforded isoxazolines 34 and 35 in very good yield and excellent regio-and enantioselectivities in the major regioisomer 34 (Scheme 10).…”

mentioning

confidence: 97%

Mini-Review: Organic Catalysts in the 1,3-Dipolar Cycloaddition Reactions of Nitrile Oxides

Roscales¹,

Plumet²

2019

HETEROCYCLES

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In 1961, Huisgen categorized the nitrile oxides (NOs) as a member of a broader class of 1,3-dipoles that were capable of undergoing 1,3-dipolar cycloaddition (DC) reactions. Nevertheless, the cycloaddition (CA) reactions of NOs to alkenes and alkynes are in many cases hampered by the tendency to the dimerization of the NO to the related furoxan (1,2,5-oxadiazole-2-oxide). In addition, although monosubstituted alkenes and alkynes show high regioselectivity in their cycloadditions with NOs, 1,2-disubstituted derivatives often give mixtures of regioisomers. Catalyzed NOs cycloadditions constitute in many cases an appropriate response to these problems and, in particular, the metal catalyzed cycloaddition reactions have been extensively used. However, the cost, toxicity and removal of trace amounts of the metal residues from desired products is quite costly and challenging, while crucial, especially in the pharmaceutical industry. Obviously, alternative pathways under metal-free conditions to fulfill the metal-catalyzed reactions are highly appealing. The present review is devoted to the consideration of the use of organic molecules as catalysts for 1,3-dipolar cycloaddition reactions of nitrile oxides. CONTENTS

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Application of chiral ligands: carbohydrates, nucleoside-lanthanides and other Lewis acid complexes to control regio- and stereoselectivity of the dipolar cycloaddition reactions of nitrile oxides and esters

Abstract: Enantioselectivity of the cycloaddition up to 99.8%.

Cited by 14 publications

References 46 publications

Evaluation of gem-Diacetates as Alternative Reagents for Enzymatic Regio- and Stereoselective Acylation of Alcohols

Evaluation of gem-Diacetates as Alternative Reagents for Enzymatic Regio- and Stereoselective Acylation of Alcohols

Nitrile Oxide, Alkenes, Dipolar Cycloaddition, Isomerization and Metathesis Involved in the Syntheses of 2-Isoxazolines

Mini-Review: Organic Catalysts in the 1,3-Dipolar Cycloaddition Reactions of Nitrile Oxides

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