Publications > Milián et al
Metal-Free Temperature-Controlled Regiodivergent Borylative Cyclizations of Enynes: BCl(3) -Promoted Skeletal Rearrangement.
Universidad de Alcalá (IRYCIS). Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río" (IQAR). Campus Científico-Tecnológico, Facultad de Farmacia, Autovía A-II, Km 33.1, 28805-Alcalá de Henares, Madrid, Spain.
Keywords: Boron; Cyclization; Enynes; Phenanthrenes; Rearrangement
Abstract
Metal-free borylative cyclization of biphenyl-embedded 1,3,5-trien-7-ynes in the presence of simple and inexpensive BCl(3) provided synthetically useful borylated building blocks. The outcome of the process depends on the reaction temperature, with borylated phenanthrenes obtained at 60 °C and phenanthrene-fused borylated cyclobutanes formed at 0 °C. Based on DFT calculations, a mechanism for these novel transformations has been proposed, which involves an uncommon skeletal rearrangement, including migration of a methyl group and alkyne fragmentation, unprecedented in BCl(3) -promoted cyclization reactions.
