Current Organic Synthesis, Volume 2, No. 2, 2005
Contents
Carbohydrate Scaffolds for the Production of Bioactive
Compounds Pp.153-173
Strategies of Synthetic Methodologies for Constructing
β-Mannosidic Linkage Pp.175-213
E.
S. H. El Ashry, N. Rashed and E. S. I. Ibrahim
Synthetic Strategies Towards O6-Substituted
Guanine Derivatives and their Application in Medicine Pp.215-230
Reagents for Carbonyl Methylenation in Organic
Synthesis Pp.231-259
Ian
Beadham and Jason Micklefield
Progress in the Synthesis of Guanacastepenes Pp.261-279
Mirta
Mischne
Oxyfunctionalization of Alkenes by Dye-Sensitized
Intrazeolite Photooxygenation Pp.281-299
Manolis
Stratakis
Abstracts
[Back to top] Carbohydrate Scaffolds for the Production of Bioactive
Compounds
L. Cipolla, F. Peri, B. La Ferla, C. Redaelli and F. Nicotra
Recent efforts in the use of carbohydrates as scaffolds for the production of bioactive compounds are reported. Orthogonally protected and solid phase supported monosaccharides for the production of libraries, exploiting the combinatorial approach by derivatisation of each hydroxyl group with different pharmacophores, are described. Example of peptidomimetics synthesised on a carbohydrate skeleton orienting proper amino acid residues, are also reported. In order to increase the conformational rigidity of the sugar templates, a variety of original bicyclic or policyclic polyfunctionalised structures have been synthesised from carbohydrates. Same of them have spiro or condensed bicyclic structures, others include one or more sugars in a macrocyclic framework or in cyclopeptides in order to induce bioactive peptide loops.
[Back to top] Strategies of Synthetic Methodologies for Constructing β-Mannosidic
Linkage
E.
S. H. El Ashry, N. Rashed and E. S. I. Ibrahim
The various synthetic methodologies for constructing the β-mannosidic bonds have been reviewed. Different strategies are covered such as inter and intramolecular glycosidation methods as well as epimerization of β-glucosides, reductive cleavage of anomeric orthoesters, radical anomeric inversion, enzymatic synthesis and mannosides from non-carbohydrate.
[Back to top] Synthetic Strategies Towards O6-Substituted
Guanine Derivatives and their Application in Medicine
R.
Schirrmacher, E. Schirrmacher, U. Muhlhausen, B. Kaina and B. Wängler
This article focuses on the synthesis of O6-substituted guanine derivatives and their application in medicine. O6-substituted guanines with alky-, aryl and heteroaryl-substituents and sterically challenging substituents have been described. The synthetic strategies are mainly based on different leaving groups in the 6-position of the guanine. Here, synthesis of various derivatives are described as well as the different synthetic pathways to obtain the synthetic precursors, which are prerequisites for efficient syntheses.
[Back to top] Reagents for Carbonyl Methylenation in Organic Synthesis
Ian
Beadham and Jason Micklefield
The methylenation of carbonyl compounds in the areas of natural and non-natural products chemistry is described herein. Phosphorus, sulfur and silicon-based reagents are compared with more recent systems based on boron, zinc and titanium and the relative merits of each reagent are discussed. Particular attention is paid to methods, which can overcome the problems associated with sterically hindered or enolizable aldehydes and ketones.
[Back to top] Progress
in the Synthesis of Guanacastepenes
Mirta Mischne
Guanacastepene A is a novel diterpene isolated from cultures of an unidentified fungus growing on the tree Daphnopsis americana. Its new molecular structure and its interesting biological property as antibiotic render this compound an attractive synthetic target. This review aims to summarise the chemistry associated to the construction of this molecule including synthetic strategies developed for the elaboration of related model systems.
[Back to top] Oxyfunctionalization
of Alkenes by Dye-Sensitized Intrazeolite Photooxygenation
Manolis Stratakis
This review focuses on the recent achievements towards the selective formation of allylic hydroperoxides by the reaction of singlet molecular oxygen (1O2) with alkenes adsorbed in the cavities of zeolite Na-Y. The product distribution by zeolite confinement is often dramatically different compared to the photooxygenation reaction in a homogeneous medium. Cation – π interactions and cation – singlet oxygen interactions, in the rate-limiting transition states, are most likely responsible for the changes in product selectivity within Na-Y.