Hydrophobically Directed Organic Synthesis

摘要

The recent surge of interest, as well as progress, in the use of water as a solvent for synthetic chemistry holds great promise for the future in terms of the cheaper and less-hazardous production of chemicals. Researchers in this area are also discovering that water may offer new possibilities in organic synthesis because of its unique physical and chemical properties that so clearly distinguishes it from other solvents.[1] Recently, significant advances have been made towards directing the selectivity of synthetic organic reactions in water through the interaction of nonpolar, or hydrophobic, regions of the reactants. These forces are normally too weak to compete with any steric and electronic effects in organic solvents. In water, on the other hand, hydrophobic surfaces associate strongly as a result of the tendency of water to exclude nonpolar species and thus minimize the Gibbs energy of solvation, a phenomenon known as the hydrophobic effect. In other words, reactions in water may be predisposed to favor transition states that optimize hydrophobic interactions. Thus, it should in principle be possible to use hydrophobic interactions as a nonbonding element of control for synthetic reactions in water.