Presentazione dei piu' moderni e attualmente usati sistemi catalitici organici sia achirali che chirali. Particolare attenzione sarà dedicata ai catalizzatori enantiomericamente puri e alla loro applicazione in sintesi stereoselettive.
The course presents an introduction to general concepts in "green" organic synthesis, the definition of organic catalysts and a general overview of the several reactions promoted by metal-free catalytic systems (8 hours) Then the concept of organocatalyst will be presented, several classes and possible action mechanisms will be considered. The most important examples of metal-free catalysts will be discussed, first in the field of aminocatalysis (8 hours). Then catalysis through immonium salts, generated by reactions with enantiomerically pure secondary amines will be deeply investigated (8 hours). The use of chiral Lewis bases will be discussed, also in combination with trichlorosilyl derivatives to generate novel chiral Lewis acids (8 hours). Alkaloids derivatives and aminoacids-derived compounds will be also discussed, specially as building blocks for the design and synthesis of bifunctional catalysts (8 hours). Finally phase transfer catalysts and chiral Bronsted acids will be presented as novel organocatalysts (4 hours) Detailed mechanistic investigations on the mode of action of different typologies of chiral oranic catalysts will be discussed. Finally examples of supported organocatalysts will be presented, the recoverability and recyclability of the systems will be discusse ( 4 hours).