Chelation-assisted Rh(I)-catalyzed ortho-alkylation of aromatic ketimines or ketones with olefins.
Described herein is the Rh(I)-catalyzed ortho-alkylation of aromatic ketimines or ketones with olefins. This method showed high reactivity and selectivity to monoalkylation for a variety of olefins including 1-alkenes with an allylic proton, alpha,omega-dienes, and internal olefins. For a mechanistic study, H/D exchange experiments were carried out, which demonstrated that the ortho C-H bond could be easily cleaved even at the low temperature of 45 degrees C. The key step of this reaction is the formation of a stable five-membered metallacycle by a chelation-assisted ortho C-H bond activation. Furthermore, the direct ortho-alkylation of aromatic ketones with the Rh(I) complex was successfully achieved by adding 50 mol % of benzylamine as a chelation-assistant tool.
Jun
Chul-Ho
CH
Department of Chemistry, Yonsei University, Seoul, South Korea. junch@yonsei.ac.kr
Moon
Choong Woon
CW
Hong
Jun-Bae
JB
Lim
Sung-Gon
SG
Chung
Kwan-Yong
KY
Kim
Yeon-Hee
YH