Aminosulf(ox)ides as Ligands for Iridium(I)-Catalyzed Asymmetric Transfer Hydrogenation
作者:Daniëlle G. I. Petra、Paul C. J. Kamer、Anthony L. Spek、Hans E. Schoemaker、Piet W. N. M. van Leeuwen
DOI:10.1021/jo991700t
日期:2000.5.1
series of chiral N,S-chelates (6-22) was synthesized to serve as ligands in the iridium(I)-catalyzed reduction of ketones. Both formic acid and 2-propanol proved to be suitable as hydrogen donors. Sulfoxidation of an (R)-cysteine-based aminosulfide provided a diastereomeric ligand family containing a chiral sulfur atom. The two chiral centers of these ligands showed a clear effect of chiral cooperativity
针对不对称酮的不对称转移加氢,开发了一类新型的高效催化剂。合成了一系列手性N,S-螯合物(6-22),用作铱(I)催化的酮还原中的配体。甲酸和2-丙醇均被证明适合作为氢供体。(R)-半胱氨酸基氨基硫化物的磺化氧化提供了包含手性硫原子的非对映体配体家族。这些配体的两个手性中心显示出明显的手性协同作用。另外,合成了在骨架中含有两个不对称碳原子的氨基硫化物。含亚砜的β-氨基醇和源自1的氨基硫化物 2-二取代的氨基醇在各种酮的还原中产生高的反应速率和中等至优异的对映选择性。通过选择最合适的氢供体,有利地影响了反应的对映选择性。在芳基-烷基酮的还原中,达到高达97%的对映选择性。