RICERCA ITALIANA     

CYCLOADDITIONS WITH REDUCED ENVIRONMENTAL IMPACT FOR THE SYNTHESIS OF PRODUCTS OF BIOLOGICAL INTEREST

Università degli Studi di Firenze

Abstract

This project is submittet by five research units whose participants are all components of the "Centro Interuniversitario sulle Reazioni Pericicliche" (http://www.unifi.it/cirp/).
It is inserted in one of the top areas of the organic chemistry, since the pericyclic reactions are one of the best ways towards a stereocontrolled synthesis of products of biological interest. This goal is not the only scope of the project. The intent is to set up new synthetic methodologies involving environmental friendly processes, both by acting on the reaction medium (e.g. ionic solvents, melted sugars) and through the development of reaction conditions (e.g. biocatalysis, microwaves, ultrasound, solar energy) able to minimize the waste release. This will be achieved by setting new processes applying the "atom economy" concept in order to exploit enhancing of stereo-selectivities. The common and main target is the preparation of modified carbohydrates interesting in themselves or as synthons for the synthesis pseudonucleosides. The cycloaddition reactions, both homo- or hetero-Diels Alder and 1,3-dipolar cycloaddition, will be the main synthetic tools for the preparation of reagents or or key intermediates. Using these synthetic tools the control of the regiofunctionalization and of the stereochemistry of different stereocenters will be assurded.
Modified Carbohydrates
Different classes of modified carbohydrates will be prepared in enantiopure form through known or >>>

Principal Investigator

Francesco DE SARLO Università degli Studi di FIRENZE

Research Objectives

Objective of this project is the development of either PRODUCTS and/or PROCESSES by means of pericyclic reactions. The synthesis of products will be focused on targets appealing for various applications in pharmaceutical or medicinal chemistry. The research program is characterized by, as the main target, the synthesis of modified carbohydrates interesting in themselves or for the synthesis of other classes of compounds such as pseudonucleosides. The cycloaddition reactions (CR), both Diels Alder (DA) and hetero-DA and 1,3-dipolar cycloaddition (DC), will be the main synthetic tools for the preparation of reagents or key intermediates. One of the main feature of these reactions is their stereoselectivity so it will be possible to control the stereochemistry of several stereocenters, plan the formation of different diastereomers, utilize chiral synthons allowing to prepare enantiopure compounds. The whole project will be developed devoting considerable efforts to find out environmental benign processes. With this aim, the PROCESSES adopted include the use of operating methods reducing the environmental impact, such as: reduction of the number of steps in the preparation of precursors and intermediates; use of catalytic reactions, including biocatalysis; reduction or improvement of separation and purification steps, achieved in several ways: i) solid phase synthesis; ii) use of ionic solvents and other reaction media (e.g. melted carbohydrates), iii) use of microwaves >>>

Timescale

24 months

National and international background

Cycloadditions are a powerful tool in synthetic Organic Chemistry leading to heterocyclic or carbocyclic compounds from open-chain precursors in a straightforward process. This method intrinsically offers the maximum of atom economy; often the stereoselectivity can be controlled owing to the concerted nature of this kind of reactions and high regioselectivities are very common. The cycloadduct can then be employed for further elaboration, according to well established protocols. The RU offer a large experience in cycloaddition chemistry and the research program concerns the use of cycloadditions for the synthesis of polyhydroxylated compounds related to modified sugars and nucleosides. This approach not only offers excellent opportunities for stereoselective syntheses, but the project, as indicated in the title, is also focused on the development of processes with reduced environmental impact. The present research project is submitted by five research units whose participants are all components of the "Centro Interuniversitario sulle Reazioni Pericicliche" (http://www.unifi.it/cirp/). This centre was constituted in 1992 among research groups of ten italian Universities in the aim of supporting the scientific exchanges among researchers involved in studying pericyclic reactions and their synthetic applications. Every two years the "Centro Interuniversitario" organises a scientific meeting for discussing the more relevant results recently obtained.The scientific background >>>