Asymmetric Reactions Catalyzed by Chiral Metal Complexes. LXX. Steric and Electronic Effects of Substrates and Rhodium Chiral Catalysts in Asymmetric Cyclopropanation.
作者:Kiyoshi YOSHIKAWA、Kazuo ACHIWA
DOI:10.1248/cpb.43.2048
日期:——
We have prepared several new, efficient, chiral N-acyl pyrrolidine carboxylic acid ligands for dirhodium-catalyzed asymmetric cyclopropanation and found that the steric and electronic effects of the rhodium(II) complexes and substrates influenced the enantioselectivity and catalytic activity. These electron-rich catalysts were shown to be efficient for asymmetric cyclopropanation using 1-chloro-1-fluoroethylene as a substrate.
Palladium-Catalyzed Enantioselective C(sp<sup>3</sup>)–H Arylation of 2-Propyl Azaaryls Enabled by an Amino Acid Ligand
作者:Hong-Liang Li、Deng-Feng Yang、Hua-Qing Jing、Jon C. Antilla、Yoichiro Kuninobu
DOI:10.1021/acs.orglett.1c04215
日期:2022.2.18
A palladium(II)-catalyzed enantioselective arylation of unbiased secondaryC(sp3)–H bonds was developed. The enantioselectivity was controlled by the combination of a pyridyl or isoquinolinyl directinggroup and an amino acid, N-Boc-2-pentyl proline. A variety of 2-propyl azaaryls and biaryl iodides were employed to provide arylated products in moderate to good yields (up to 82%) with high enantioselectivities