convenient promoter for Ferrier-type rearrangement of 3,4,6-tri-O-benzyl-d-glucal in CH2Cl2, which is a difficult donor for this type of reaction. The acceptors include primary alcohols, secondary alcohols, pentanol, halogenated alcohol, sterols, thiol, and 2-naphthol. Thus, 2,3-unsaturated glycosides were obtained rapidly (<2 h) and efficiently (>62%) in good α-selectivity (α/β>4.2:1) under mild conditions
Abstract FeCl3/C was used as an efficient and convenient promoter for glycosylation through Ferrier-type rearrangement of 3,4,6-tri-O-benzyl-D-glucal, which is a relatively unreactivesubstrate for this type of reaction. The method was applicable to a wide range of alcohols, especially phenols. A series of 2,3-unsaturated-O-glucosides were prepared efficiently (47–92%) by this method under mild conditions
Gd(OTf) 3 catalyzed preparation of 2,3-unsaturated O -, S -, N -, and C -pyranosides from glycals by Ferrier Rearrangement
作者:Peiran Chen、Jie Su
DOI:10.1016/j.tet.2015.11.002
日期:2016.1
By using Gd(OTf)3 as the catalyst, synthesis of 2,3-unsaturated-glycosides has been performed by FerrierRearrangement. A series of 2,3-unsaturated O-, S-, N-, and C-glycosides were obtained from 3,4,6-tri-O-acetyl-d-glucal, 3,4,6-tri-O-benzyl-d-glucal, and 3,4-di-O-acetyl-l-rhamnal under mild reaction conditions in good yields and high anomeric selectivities.
2,3-Unsaturated Allyl Glycosides as Glycosyl Donors for Selective α-Glycosylation
作者:Brijesh Kumar、Mushtaq A. Aga、Abdul Rouf、Bhahwal A. Shah、Subhash C. Taneja
DOI:10.1021/jo102333x
日期:2011.5.6
presence of NBS and a catalytic amount of a Lewis acid, 2,3-unsaturated allylglycosides [6-(allyloxy)-3,6-dihydro-2-(hydroxymethyl)-2H-pyran-3-ol] have been successfully used as versatile glycosyl donors for the stereoselective α-glycosylation of a variety of alcohols comprising sensitive functions such as acetonide, keto, nitro, and ester in 50−90% yields. The methodology offers an equally facile alternative
Aluminium triflate catalysed O-glycosidation: temperature-switched selective Ferrier rearrangement or direct addition with alcohols
作者:D. Bradley G. Williams、Sandile B. Simelane、Henok H. Kinfe
DOI:10.1039/c2ob25540e
日期:——
A temperature-controlled mechanism switch between the Al(OTf)3-catalysed direct addition of alcohols or the Ferrier rearrangement reactions in some glycals is presented. The scope and limitations are investigated as are the influence of the stereochemistry and nature of the protecting groups on the glycal substrate.