Pd(II)-catalyzed enantioselective borylation of C(sp3)-H bonds has been realized for the first time using chiral acetyl-protected aminomethyl oxazoline ligands. This reaction is compatible with carbocyclic amides containing α-tertiary as well as α-quaternary carbon centers. The chiral β-borylated amides are useful synthons for the synthesis of chiral β-hydroxylated, β-fluorinated, and β-arylated carboxylic
carboxylic acids with organoborons has been realized using either mono-protected aminoacid (MPAA) ligands or mono-protected aminoethyl amine (MPAAM) ligands. A diverse range of aryl- and vinyl-boron reagents can be used as coupling partners to provide chiral carboxylic acids. This reaction provides an alternative approach to the enantioselective synthesis of cyclopropanecarboxylic acids and cyclobutanecarboxylic
Palladium(II)-Catalyzed Enantioselective C(sp<sup>3</sup>)–H Activation Using a Chiral Hydroxamic Acid Ligand
作者:Kai-Jiong Xiao、David W. Lin、Motofumi Miura、Ru-Yi Zhu、Wei Gong、Masayuki Wasa、Jin-Quan Yu
DOI:10.1021/ja504196j
日期:2014.6.4
An enantioselective method for Pd(II)-catalyzed cross-coupling of methylene β-C(sp3)–H bonds in cyclobutanecarboxylic acid derivatives with arylboron reagents is described. High yields and enantioselectivities were achieved through the development of chiral mono-N-protected α-amino-O-methylhydroxamic acid (MPAHA) ligands, which form a chiral complex with the Pd(II) center. This reaction provides an