Ligand-Promoted, Boron-Mediated Chemoselective Carboxylic Acid Aldol Reaction.
The first carboxylic acid selective aldol reaction mediated by boron compounds and a mild organic base (DBU) was developed. Inclusion of electron-withdrawing groups in the amino acid derivative ligands reacted with BH3·SMe2 forms a boron promoter with increased Lewis acidity at the boron atom and facilitated the carboxylic acid selective enolate formation, even in the presence of other carbonyl groups such as amides, esters, ketones, or aliphatic aldehydes. The remarkable ligand effect led to the broad substrate scope including biologically relevant compounds.
Graduate School of Pharmaceutical Sciences, The University of Tokyo , 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Hideoki
H
Nagai
Graduate School of Pharmaceutical Sciences, The University of Tokyo , 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Yuya
Y
Morita
Graduate School of Pharmaceutical Sciences, The University of Tokyo , 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Yohei
Y
Shimizu
Graduate School of Pharmaceutical Sciences, The University of Tokyo , 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.|ERATO, Japan Science and Technology Agency, Kanai Life Science Catalysis Project, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Motomu
M
Kanai