Practical P-Chiral Phosphane Ligand for Rh-Catalyzed Asymmetric Hydrogenation
作者:Duan Liu、Xumu Zhang
DOI:10.1002/ejoc.200400690
日期:2005.2
conformationally rigid P-chiral bis(trialkylphospholane) ligand 2 (DuanPhos) has been prepared in both enantiomeric forms through a concise syn-thesis. Rh-2 complex has exhibited remarkably high enantio-selectivities (up to >99% ee) and reactivities (up to 10,000 TON) for the hydrogenation of a wide variety of functionalized prochiral alkenes (5 different types), which provides a very practical catalytic system
Nickel-Catalyzed Asymmetric Transfer Hydrogenation of Olefins for the Synthesis of α- and β-Amino Acids
作者:Peng Yang、Haiyan Xu、Jianrong Steve Zhou
DOI:10.1002/anie.201407744
日期:2014.11.3
The field of asymmetric (transfer) hydrogenation of prochiral olefins has been dominated by noble metal catalysts based on rhodium, ruthenium, and iridium. Herein we report that a simple nickel catalyst is highly active in the transfer hydrogenation using formic acid. Chiral α‐ and β‐amino acid derivatives were obtained in good to excellent enantioselectivity. The key toward success was the use of
Novel chiralmonodentate phosphorus ligands, SIPHOS, were conveniently synthesized from 1,1‘-spirobiindane-7,7‘-diol. The Rh complexes of SIPHOS can catalyze the hydrogenation of α-dehydroaminoesters in mild conditions, providing α-amino acid derivatives in up to 99% ee. Enamides and β-dehydroamino esters can also be hydrogenated in good to excellent enantioselectivities (up to 99% and 94% ee, respectively)
More electron donating, more rigid: A new highly electron‐donating P‐stereogenic bisphospholaneligand (ZhangPhos) was synthesized in a practical and highlyenantioselective manner from a commercially available chiral source. Better or comparable enantioselectivities and reactivities than TangPhos were achieved in rhodium‐catalyzed hydrogenation of various functionalized olefins (see scheme; nbd=3
Nickel-catalyzed enantioselective umpolung hydrogenation for stereoselective synthesis of β-amido esters
作者:Jianrong Steve Zhou、Siyu Guo、Xiaohu Zhao、Yonggui Robin Chi
DOI:10.1039/d1cc05257h
日期:——
Nickel complexes ligated by strongly donating diphosphines catalyze enantioselective hydrogenation for the preparation of acyclic and cyclic β-amido esters. A combination of aceticacid and indium powder provides protons and electrons to form nickel hydrido complexes under umpolung hydrogenation conditions.