Strategies for protection and deprotection of OH-groups in the presence of phosphines have been explored. Rate acceleration in the Baylis-Hillman reaction was observed when a hydroxyl phosphine was used as the catalyst. Rhodium complexes with chiral bisphospholanes are highly enantioselective catalysts for the asymmetrichydrogenation of various kinds of functionalized olefins such as dehydroamino
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
Biocatalytic, Intermolecular C−H Bond Functionalization for the Synthesis of Enantioenriched Amides
作者:Soumitra V. Athavale、Shilong Gao、Zhen Liu、Sharath Chandra Mallojjala、Jennifer S. Hirschi、Frances H. Arnold
DOI:10.1002/anie.202110873
日期:2021.11.15
P411 heme enzymes enables intermolecular C−H amidation with high yields and exquisite enantioselectivity. The biocatalytic process utilizes stable hydroxamate esters as nitrenoid precursors and is amenable to scaleup. Mechanistic studies reveal rate-determining nitrenoid formation followed by a stepwise, hydrogen atom transfer-mediated C−Hfunctionalization.
Six-membered bis(azaphosphorinane), readily available ligand for highly enantioselective asymmetric hydrogenations
作者:Yongjun Yan、Xumu Zhang
DOI:10.1016/j.tetlet.2006.01.003
日期:2006.3
A new six-membered bis(azaphosphorinane) ligand has been readily prepared starting from an inexpensive chiral epoxide; excellent enantioselectivities (up to over 99% ee) have been achieved in the Rh-catalyzed asymmetric hydrogenations of β-dehydroamino acid derivatives and α-arylenamides.
A Chemoenzymatic Approach to Enantiomerically Pure Amines Using Dynamic Kinetic Resolution: Application to the Synthesis of Norsertraline
作者:Lisa K. Thalén、Dongbo Zhao、Jean-Baptiste Sortais、Jens Paetzold、Christine Hoben、Jan-E. Bäckvall
DOI:10.1002/chem.200802303
日期:2009.3.23
Dynamic transformation: A racemization catalyst and the enzyme Candida antarctica lipase B (CALB) were combined in a one‐pot dynamic kineticresolution (DKR) of primary amines, which were transformed to their corresponding amides in up to 95 % yield and >99 % ee. This chemoenzymatic DKR was also applied to the synthesis of norsertraline (see scheme).