Showing papers on "Ferrier rearrangement published in 2005"
TL;DR: Alkyl 2,3-unsaturated glycopyranosides have been prepared by the Ferrier rearrangement of acetyl protected glycals catalyzed by HClO 4 -SiO 2 as discussed by the authors.
Abstract: Alkyl 2,3-unsaturated glycopyranosides have been prepared by the Ferrier rearrangement of acetyl protected glycals catalyzed by HClO 4 -SiO 2 . Operational simplicity, use of economically convenient catalyst, mild reaction conditions, high yields, short reaction times are the key features of this protocol.
68 citations
TL;DR: The total synthesis of (-)-kendomycin was achieved in 21 steps exploiting an effective Petasis-Ferrier union/rearrangement tactic to construct the tetrahydropyran ring, a ring-closing metathesis to generate the macrocycle, and a biomimetic quinone-methide-lactol assembly.
Abstract: The total synthesis of (−)-kendomycin (1), a novel macrocyclic polyketide with antibacterial and antitumor activity, was achieved in 21 steps (longest linear sequence) exploiting an effective Petasis−Ferrier union/rearrangement tactic to construct the tetrahydropyran ring, a ring-closing metathesis to generate the macrocycle, and a biomimetic quinone−methide−lactol assembly.
60 citations
TL;DR: Bi(OTf)3 and SiO2-Bi3 are found to effectively catalyze the Ferrier rearrangement of tri-O-acetyl glycals with different alcohols providing an effective route to 2,3-unsaturated O-glycosides with good anomeric selectivity and good to excellent yields after short reaction times.
Abstract: Bi(OTf)3 and SiO2-Bi(OTf)3 are found to effectively catalyze the Ferrierrearrangement of tri-O-acetyl glycals with different alcohols providing an effective routeto 2,3-unsaturated O-glycosides with good anomeric selectivity and good to excellentyields after short reaction times.
40 citations
TL;DR: Alkyl 2,3-unsaturated C-glycopyranosides have been prepared by Ferrier rearrangement of acyl or alkyl protected glycals catalyzed by HClO(4)-SiO(2).
33 citations
TL;DR: Acid-mediated glycosylations of endo- and exo-glycals have been carried out in good to excellent yields, in which a mixture of two products is often obtained resulting from Ferrier rearrangement and protonation.
26 citations
TL;DR: In this paper, 2-C -acetoxymethyl glycal derivatives react with aliphatic alcohols in the presence of InCl 3 to furnish the corresponding 2-c -methylene glycosides in excellent yields and with exclusive α-selectivity.
24 citations
TL;DR: Interestingly exo -glycals were found to have higher activity than endo - glycals and common glycosides, the reactions of which can be improved by the addition of Lewis acid to result in a higher yield and enhanced stereoselectivity.
Abstract: exo -Glycosyl carbonates were shown to be efficient glycosyl donors in microwave-assisted glycosylation. In these reactions α-glycosyl additions occurred with excellent stereoselectivity and were complete in 4–8 min with 75–92% yield. Interestingly exo -glycals were found to have higher activity than endo -glycals and common glycosides, the reactions of which can be improved by the addition of Lewis acid to result in a higher yield and enhanced stereoselectivity.
21 citations
TL;DR: The reaction of derivatives of 3-acetyl-d-glucal, 3-et al. with sodium benzenesulfinate in acid medium catalyzed by HgSO4 afforded diastereoisomeric mixtures of the corresponding 2,3-dideoxy-3-(phenylsulfonyl)-hexopyranoses through a Ferrier rearrangement as mentioned in this paper.
15 citations
TL;DR: The reaction of 1,2-dihydropyranyl acetates with dimethylzinc, diethylZinc and diphenylzinc in the presence of CF3COOH gave the corresponding alky and aryl C-pyranosides via a Ferrier rearrangement in excellent yields.
13 citations
TL;DR: In this article, a palladium mediated modified protocol has been developed for the glycosidation of an aromatization prone xylo-furanoid glycal for the synthesis of D-D4FC.
8 citations
TL;DR: Glycosidation of various glycals with furanic alcohols in presence of catalytic amount of ceric(IV) ammonium nitrate under neutral condition or using Lewis acid-catalysed proceeds smoothly to afford the corresponding 2,3-unsaturated glycosides in good yields as discussed by the authors.
Abstract: Glycosidation of various glycals with furanic alcohols in presence of catalytic amount of ceric(IV) ammonium nitrate under neutral condition or using Lewis acid-catalysed proceeds smoothly to afford the corresponding 2,3-unsaturated glycosides in good yields. In the hexose series predominantly α-D-anomers resulted while β-D-anomers are predominant in the pentose serie.
TL;DR: In this article, tri-O-acetyl-D-glucal 1 with various alcohols and phenols in the presence of InCl3 / CH2Cl2 at ambient temperature furnished the corresponding alkyl and aryl 2,3-unsaturated glycopyranosides in excellent yields in short reaction times and good anomeric selectivity.
Abstract: Treatment of tri-O-acetyl-D-glucal 1 with various alcohols and phenols in the presence of InCl3 / CH2Cl2 at ambient temperature furnished the corresponding alkyl and aryl 2,3-unsaturated glycopyranosides in excellent yields in short reaction times and good anomeric selectivity.
TL;DR: Application of the Ferrier rearrangement led to a novel carbohydrate based synthetic route to 4-aminohexenoic acid viz. (R) and (S)-vigabatrin and the potential of D- glucose or D-galactose as the chiral starting materials for the synthesis of (R).
Abstract: Application of the Ferrier rearrangement led to a novel carbohydrate based synthetic route to 4-aminohexenoic acid viz. (R) and (S)-vigabatrin. The potential of D- glucose or D-galactose as the chiral starting materials for the synthesis of (R) and (S)- vigabatrin has been explored.
TL;DR: Alkyl 2,3-unsaturated glycopyranosides have been prepared by the Ferrier rearrangement of acetyl protected glycals catalyzed by HClO 4 -SiO 2 as mentioned in this paper.
Abstract: Alkyl 2,3-unsaturated glycopyranosides have been prepared by the Ferrier rearrangement of acetyl protected glycals catalyzed by HClO 4 -SiO 2 . Operational simplicity, use of economically convenient catalyst, mild reaction conditions, high yields, short reaction times are the key features of this protocol.
TL;DR: The reaction of derivatives of 3-acetyl-d-glucal, 3-et al. with sodium benzenesulfinate in acid medium catalyzed by HgSO4 afforded diastereoisomeric mixtures of the corresponding 2,3-dideoxy-3-(phenylsulfonyl)-hexopyranoses through a Ferrier rearrangement as mentioned in this paper.
Abstract: The reaction of derivatives of 3-acetyl-d-glucal, 3-acetyl-l-rhamnal, 3-acetyl-d-galactal, and 3-acetyl-d-lactal with sodium benzenesulfinate in acid medium catalyzed by HgSO4 afforded diastereoisomeric mixtures of the corresponding 2,3-dideoxy-3-(phenylsulfonyl)-hexopyranoses through a Ferrier rearrangement. The anomeric alkoxyl radical fragmentation of these γ-hydroxy sulfones using the system (diacetoxyiodo)benzene and iodine gave vinyl sulfones with structures of 1,2-dideoxy-4-O-formyl-2-(phenylsulfonyl)-pent-1-enitol and configurations d-erythro, l-erythro, and d-threo at the two stereogenic centers.
TL;DR: In this article, Ferrier rearrangement and protonation are used to obtain a mixture of two products, which is then used for glycosylation of exo-glycals with allyl benzyl ether or acetate.
Abstract: Acid-mediated glycosylations of endo- and exo-glycals have been carried out in good to excellent yields, in which a mixture of two products is often obtained resulting from Ferrier rearrangement and protonation. The former reaction exclusively takes place with the t-butyl carbonate or hydroxyl substituent at the C3 position of endo-glycals, while the latter mainly occurs in the glycosylation of exo-glycals with allyl benzyl ether or acetate. In addition to the substituent effect, protecting groups are critical to determine the activity and favored reaction pathway. Furthermore, the method is applicable to O-, C-, and N-nucleophiles.
TL;DR: In this paper, the reaction of tri-O-acetyl-D-glucal with nucleophiles to afford the corresponding 2,3-unsaturated glycopyranosides in excellent yields by zirconium(IV) chloride in acetonitrile at ambient temperature has been demonstrated.
Abstract: The reaction of tri‐O‐acetyl‐D‐glucal with nucleophiles to afford the corresponding 2,3‐unsaturated glycopyranosides in excellent yields by zirconium(IV) chloride in acetonitrile at ambient temperature has been demonstrated. #IICT Communication No 021011
TL;DR: Exo -Glycosyl carbonates were shown to be efficient donors in microwave-assisted glycosylation and α-glycosyl additions occurred with excellent stereoselectivity and were complete in 4-8min with 75-92% yield as discussed by the authors.
Abstract: exo -Glycosyl carbonates were shown to be efficient glycosyl donors in microwave-assisted glycosylation. In these reactions α-glycosyl additions occurred with excellent stereoselectivity and were complete in 4–8 min with 75–92% yield. Interestingly exo -glycals were found to have higher activity than endo -glycals and common glycosides, the reactions of which can be improved by the addition of Lewis acid to result in a higher yield and enhanced stereoselectivity.