Selective Synthesis of Boron-Functionalized Indenes and Benzofulvenes by BCl(3)-Promoted Cyclizations of ortho-Alkynylstyrenes.
1. Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río" (IQAR), Universidad de Alcalá (IRYCIS), 28805 Alcalá de Henares, Madrid, Spain. 2. Área de Química Orgánica, Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Pza. Misael Bañuelos s/n, 09001 Burgos, Spain.
A selective, metal-free synthesis of boron-functionalized indenes and benzofulvenes via BCl(3)-mediated cyclization of o-alkynylstyrenes is described. The method allows precise control over product formation by adjusting reaction conditions. These borylated products were utilized in diverse C-B bond derivatizations and in the total synthesis of Sulindac, a nonsteroidal anti-inflammatory drug, demonstrating the versatility and practicality of the developed methodology for synthetic applications.