Pure Appl. Chem., 2008, Vol. 80, No. 5, pp. 1039-1045
doi:10.1351/pac200880051039
Copper-catalyzed substitution of allylic carbonates with diboron: A new approach to allylboronate synthesis*
Hajime Ito, Shinichiro Ito, Yusuke Sasaki, Kou Matsuura, and Masaya Sawamura
Department of Chemistry, Faculty of Science, Hokkaido University,Sapporo 060-0810, Japan
Abstract:
Copper-catalyzed γ-selective substitution of allylic carbonates with diboron provides a new method for the efficient synthesis of allylboronates. Optically active α-chiral allylboronates were synthesized through the reaction of chiral allylic carbonates with bis(pinacolato)diboron in the presence of achiral Cu(I)-catalyst with highly efficient chirality transfer. Additionally, in the presence of a chiral Cu(I) catalyst, optically active α-chiral allylboronates were obtained with >90 % ee through the reaction of prochiral substrates with the diboron.
Keywords: allylboronates; asymmetric; catalysis; chiral ligands; copper.
*Paper based on a presentation at the 14th International Symposium on Organometallic Chemistry Directed Towards Organic Synthesis (OMCOS-14), 2-6 August 2007, Nara, Japan. Other presentations are published in this issue, pp. 807-1194.