屋根付きcis型ジアミンを利用した高効率不斉還元反応の開発　　

抄録

We previously developed chiral "roofed" 2-imidazolidinones (DHAIm), which are conformationally rigid and sterically bulky, from the thermal [4+2] cycloaddition of a simple 5-membered heterocycle, 1,3-dihydro-2-imidazolone, with anthracene followed by optical resolution and showed to be excellent chiral auxiliaries for asymmetric C-C bond formations. Prompting these results, we applied "roofed" cis-diamine, ring-opened form of DHAIm, to catalytic asymmetric reactions as chiral ligands. Thus, a chiral Ru (II) complex, prepared from "roofed" cis-diamine and [RuCl₂(benzene)]₂, proved to be an efficient catalyst for the asymmetric transfer hydrogenation of a wide variety of aryl ketones, including sterically bulky ketones. The Ru(II) complex showed both a high catalytic activity and enantioselectivity (up to 99% ee) when the reaction was conducted in the presence of 5HCO₂H.2NEt₃.

fig.1