Stereoselective Synthesis of Enantiopure Abasic Nucleosides and 4-Nitroisoxazoles

Chapter 1

A brief overview on organocatalysis and its application in 1,4-Michael type reactions.

Chapter 2

We have described a 1,6-Michael type addition of 4-pyridilacetonitrile to 4-nitro-5-styril-isoxazoles under PTC and bifunctional catalysis.

Chapter 3

We have reported a organocatalytic 1,4-conjugate addition of 1,3-dicarbonyl compounds (i.e. acetylacetone and malonate esters) to 4-nitro-5-styril-isoxazoles under bifunctional catalysis conditions.

Chapter 4

Herein we report organocatalytic aza-Michael additions to 4-nitro-5-styril-isoxazoles of different N-nucleophiles (i.e. indoline, 1H-benzotriazole and O-benzylhydroxylamine) as Michael donors for the generation of building blocks with high potential synthetic utility.

Chapter 5

An enantioselective Michael-type conjugate addition of boronic acids, catalysed by chiral transition metal complexes, effective in the formation of C-C bonds, has been described using 4-nitro-5-styril-isoxazoles as Michael acceptors.

Chapter 6

The development of novel C-nucleosides analogues bearing functional groups able to complex divalent metal ions has been investigated. Here we describe the preparation of modified nucleosides, prepared from a cheap and readily available starting material (i.e. 2-deoxyribose).