engleski

High-Pressure Cycloaddition Reactions in the Synthesis of Biologically Relevant Heterocycles

Environment-friendly organic synthesis applies to a number of methodologies in an effort to reduce human impact to nature. Among them are synthetic methodologies which use less energy, reduce use of solvents, replace the toxic solvents and reagents with more benign ones, increase the efficiency of reactions, and reduce the production of toxic wastes. Photochemistry, microwave and ultrasonic irradiation, solvent-free mechanochemistry, extremely high pressure, and catalysis are technologies which are valuable tools in eco-friendly processes. Extremely high pressures (1–20 kbar) become the standard tool in organic synthesis. By applying such reaction conditions, many organic reactions are efficiently promoted under milder conditions with no need for a metallic catalyst and/or high temperatures. Cycloaddition reactions (Diels–Alder and dipolar) provide a rapid and convergent entry to complex molecules. For these reactions, employment of high pressure is highly beneficial in acceleration of reaction, as cycloadditions exhibit a large negative volume of activation (ΔV≠). In such conditions, chemical equilibrium is shifted toward the product. Until today, a number of cycloadditions were carried out under high pressure, including synthesis of various heterocycles. This chapter focuses on some of the recent developments in this field.

cycloadditions, high pressure, heterocycles

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