1. Sı́ntesis de Productos Naturales, Instituto de Productos Naturales y Agrobiologı́a del CSIC, Carretera de La Esperanza 3, 38206, La Laguna, Tenerife, Spain
2. WestCHEM Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, Scotland, U.K.