Me<sub>3</sub>SI-promoted chemoselective deacetylation: a general and mild protocol
作者:Aakanksha Gurawa、Manoj Kumar、Sudhir Kashyap
DOI:10.1039/d1ra03209g
日期:——
Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developed via employing KMnO4 as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses
Highly stereoselective addition of organozinc reagents to pentopyranose derived glycals: effect of protecting group and assignment of C-glycoside stereochemistry
The nucleophilic addition of ethyl 3-propionylzinc iodide to a variety of differently protected pentopyranose derived d-glycals 6a–g proceeds with good to high levels of diastereoselectivity to provide the corresponding β-C-glycosides 7. The stereochemistry of the para-nitrobenzoate derivative 7d has been confirmed by X-ray crystallography, and the stereochemistry of the other β-C-glycoside products
Stereoselective Conjugate Addition of Mixed Organoaluminum Reagents to α,β-Unsaturated<i>N</i>-Acyloxazolidinones Derived from Carbohydrates
作者:Horst Kunz、Stephan Elzner、Steffen Maas、Stefan Engel
DOI:10.1055/s-2004-831173
日期:——
β-branched carboxylic acid derivatives was accomplished by conjugateaddition of mixed organoaluminum reagents to chiral α,β-unsaturated N-acyloxazolidinones. Mixed organoaluminum reagentswere generated in situ by transmetalation of Grignard or organolithium compounds with methylaluminum dichloride. Efficient stereocontrol was achieved using different bicyclic glycosamine-derived oxazolidinones, yielding
Total synthesis of (+)-cacospongionolide B was achieved. The synthesis involved highly stereoselective C-glycosidation of a glycal derived from D-arabinose with 3-furyl boronic acid in the presence of a palladium catalyst and B-alkyl Suzuki-Miyaura coupling of in situ generated alkylborane prepared by the reaction of vinyl trans-decalin with alkenyl triflate.
Benzyl Esters of D- and L-Arabinals as Chiral Synthons in Organic Synthesis
作者:A. G. Tolstikov、N. V. Khakhalina、L. V. Spirikhin
DOI:10.1055/s-1988-27518
日期:——
An acidic opening of the benzyl esters of D and L arabinal (1,5-anhydro-2-deoxy-erythro-pent-1-enitol) catalyzed by mercuric sulfate has been proposed as the key step in the preparation of chiral synthons with selectively substituted hydroxy groups.