1. Origin of reactivity in water

Water is the solvent in which nature carries out all the chemical transformations associated with life. Organic chemists, on the other hand, have tended to avoid this medium and work in anhydrous conditions. There are several reasons for this, the main one being that most organic molecules are poorly soluble in this medium, if not insoluble; moreover, many reagents are not stable in water, so researchers have abandoned the idea of developing syntheses that can be carried out in aqueous media. But this was not always the case. Indeed, the beginnings of synthetic chemistry are attributed to the German chemist Wöhler, who prepared urea by heating an aqueous solution of ammonium isocyanate. The year was 1828... Water remained a solvent for the transformation of organic molecules until the advent of organometallic chemistry, which imposed anhydrous...