Synthesis of optically active rare earth metal complexes as chiral catalysts or reagents in organic synthesis

摘要

The development and utilization of new lanthanoid complexes as catalysts or reagents in asymmetric synthesis are currently of intense interest. Recently, we prepared several optically active rare earth metal complexes which work as (1) a chiral Lewis acid catalyst, (2) a chiral base catalyst, or (3) a chiral one-electron transfer agent. (1) Asymmetric hetero Diels-Alder reaction of carbonyl compounds with a diene was effectively catalyzed by optically active rare earth metal complexes hearing chiral phosphate ligands to give the cycloadducts with high enantioselectivity (up to 97 percent ee). (2) Remarkably high enantioselectivity (up to >99.9percent ee) and asymmetric amplification was observed in the chiral La/(R)-BINOL/triphenylphosphine oxide complex-catalyzed epoxidation of enones with cumene hydroperoxide as an oxidant (3) The chiral samarium(II) complex prepared from Sml2, (R )-BINOL, and TMEDA promoted the reductive homo-coupling reaction of #beta#-monosubstituted acrylic acid amides to give the corresponding 3,4-trans-disulstituted pimelic acid amides with high enantioselectivity (up to 85 percent ee).