Enokipodins comprises a family of sesquiterpenes isolated from the mushroom Flammulina velutipes. These substances are attractive synthetic targets due to either their biological potential or structural characteristics. Since their isolation, about a decade ago, a considerable number of successful total syntheses have been published. Both via a racemic or enantioselective approach, these studies describe original and creative synthetic routes, particularly concerning the methodology used for constructing the benzylic quaternary center of these natural products. In this brief review, we discuss the reported total synthesis of enokipodins, focusing on the strategy adopted for the quaternary stereogenic center.

Guanil-hidrazonas poli-substituídas foram sintetizadas através da reação de guanilação de tiossemicarbazonas com aminas aromáticas e alifáticas, promovida HgCl2. Este método representa o primeiro emprego de tiossemicarbazonas como componente eletrofílico em reações de síntese de guanidinas mediadas por tiófilo, onde a introdução de cada substituinte dos nitrogênios das guanil-hidrazonas ocorreu de forma regiosseletiva. As atividades antibacteriana e antifúngica foram avaliadas e alguns derivados mostraram atividade em valores pequenos de concentração inibitória mínima e com amplo espectro de atividade. Estudou-se a estrutura cristalina de duas guanil-hidrazonas, determinando-se suas configurações e, as únicas interações relevantes observadas foram intermoleculares do tipo N-H...N e C-H...N.

Thiosemicarbazones were employed for the first time as electrophiles in the guanylation reaction promoted by HgCl2, affording polysubstituted guanylhydrazones, with regioselective introduction of each nitrogen substituent. The antibacterial and antifungal activities of guanylhydrazones were evaluated by determination of minimal inhibitory concentrations. Some of them exhibited very low minimal inhibitory concentrations (MIC) and broad-spectrum activities. The configurations of two guanylhydrazones were assigned by X-ray analysis that also revealed intramolecular interactions of the type N-H...N and C-H...N.