Synthesis of homochiral pentadentate sulfonamide-based ligands
摘要:
A two-step synthesis of pentadentate, tetraionic ligands based on sulfonamide, amide, and pyridyl groups is reported. These ligands are easily accessible in good to excellent yield from commercially available materials. (C) 2001 Elsevier Science Ltd. All rights reserved.
New efficient catalysts for enantioselective transfer hydrogenations
作者:Kurt Püntener、Lothar Schwink、Paul Knochel
DOI:10.1016/0040-4039(96)01853-9
日期:1996.11
New C2-symmetrical diaminoferrocenyl derivatives 3 and 2-amino(sulfonamido)cyclohexanes 4 were found to be highly active ligands for the ruthenium catalyzed asymmetric transferhydrogenation of ketones. Contrary to many existing catalytic systems, the ligands 3 show a high activity at 25 °C and operate even at −30 °C (up to 90 % ee). On the other hand, the slightly less active ligands 4 are very easily
发现新的C 2-对称的二氨基二茂铁基衍生物3和2-氨基(磺酰胺基)环己烷4是钌催化的酮的不对称转移氢化的高活性配体。与许多现有的催化体系相反,配体3在25°C时表现出高活性,甚至在−30°C(高达90%ee)下运行。另一方面,活性稍低的配体4非常容易制备,并且在30℃下在HCOOH / Et 3 N(至多96%ee)中具有高对映选择性。