Catalytic Enantioselective Addition of Cyclic β-Keto Esters with Activated Olefins and N-Boc Imines Using Chiral <i>C</i><sub>2</sub>-Symmetric Cationic Pd<sup>2+</sup> N-Heterocyclic Carbene (NHC) Diaqua Complexes
作者:Zhen Liu、Min Shi
DOI:10.1021/om100331z
日期:2010.6.28
The asymmetric addition of cyclic β-keto esters to activated olefins and N-Boc imines was realized by using chiral cationic C2-symmetric N-heterocyclic carbene (NHC) Pd2+ diaqua complexes 1a,b as the catalysts, producing the corresponding adducts in moderate to high yields (up to 95%) and with good to high enantioselectivities (up to 96% ee). Nevertheless, the most significant observation is that when
Dinuclear Ni<sub>2</sub>–Schiff base complex-catalyzed asymmetric 1,4-addition of β-keto esters to nitroethylene toward γ<sup>2,2</sup>-amino acid synthesis
作者:Harunobu Mitsunuma、Shigeki Matsunaga
DOI:10.1039/c0cc02152k
日期:——
A homodinuclear Ni(2)-Schiffbase 1 complex (1-10 mol%) promoted the catalyticasymmetric1,4-additionreactions of beta-keto esters and an N-Boc oxindole to nitroethylene, giving products in 98-75% ee.