1. a Department of Inorganic Chemistry, Faculty of Chemistry , University of Havana , Havana 10400 , Cuba
2. b Organic Synthesis Laboratory, Faculty of Chemistry , University of Havana , Havana 10400 , Cuba
3. c Chemistry Institute, UNAM , Cayoacán 04510 , México D.F. , México
4. d Department of Organic Chemistry , University of Cádiz , Cádiz , Spain
5. e Instituto de Física de Sao Carlos, Universidade de Sao Paulo , Sao Paulo , Brazil