Extending the synthetic utility of p-quinols: hetero Michael-type additions and Friedel-Crafts reactions

Résumé

The p-quinol (4-alkyl-4-hydroxy-2,5-cyclohexadienone) moiety is frequently present in a great number of natural products with simple or complex structures. Some of them show a wide range of interesting biological properties such as antitumoral1 and trypanocides2. Examples of natural p-quinols with simple structures are shown in Figure 1.1. Jacaranone was isolated in 1999 from the Ajuga pasiflora3, an endemic plant from Afganistan and Pakistan which has been used against a high number of deseases and infections, and presents a high cytotoxic and antitumoral activity. Glycoside, known as well as Cornoside, has been isolated from different plants such as Tecota capensis,4 Abeliophyllum distichum,5 Cornelius canadensis,6 Polypremum procumbens7 and Tetrachondra hamiltonii.7 Directly related to the glycoderivative was the acetate Hallerone obtained from Halleria lucida8 and Phyla nodiflora.