The environmentally amiable route to carbon-heteroatom bond formation, described by Sharpless as ‘click chemistry’, has become known as a fast, efficient, and reliable approach to the synthesis of novel compounds with desired functionalities. Readily available starting materials must be used in this methodology and they should be essentially inert to most biological and organic conditions, including water and molecular oxygen. In this review, we cover reactions included in this label such as cycloadditions, nucleophilic ring-opening reactions of strained cycles, and amide synthesis, as well as their applications in organic synthesis, molecular biology, macromolecular chemistry and materials science.

Insecticides have a pivotal role in our lives, not only for crop protection in agriculture, but also to avoid the spreading of harmful pests causing human diseases such as malaria. Due to economic and medical reasons, the design of effective agents that control these pests is quite an important task in agrochemical science and in the industrial sector. Nevertheless, the non-restricted use of highly toxic insecticides for several decades has provoked negative effects in the environment and the poisoning of non-targeted species. For these reasons, the development of selective and harmless insecticides is needed. A short overview of some of the recent advances in the chemistry of insecticides is presented, with a highlight of their greenness compared with classical insecticides. Synthesis, mode of action and environmental profile of pyrethroids, neonicotinoids, and insect growth regulators will be described. Furthermore, the use of biological insecticides such as spinosyns, azadirachtin, and Bacillus thuringiensis as green alternatives for synthetic insecticides will also be reviewed.