Novel, Tunable, and Efficient Chiral Bisdihydrobenzooxaphosphole Ligands for Asymmetric Hydrogenation
摘要:
A series of novel, efficient, air-stable, and tunable chiral bisdihydrobenzooxaphosphole ligands (BIBOPs) were developed for rhodium-catalyzed hydrogenations of various functionalized olefins such as alpha-arylenamides, alpha-(acylamino)acrylic acid derivatives, beta-(acylamino)acrylates, and dimethyl itaconate with excellent enantioselectivities (up to 99% ee) and reactivities (up to 2000 TON).
A Versatile and Practical Solvating Agent for Enantioselective Recognition and NMR Analysis of Protected Amines
作者:Daniel P. Iwaniuk、Christian Wolf
DOI:10.1021/jo101426a
日期:2010.10.1
The 3,5-dinitrobenzoyl-derived 1-naphthylethyl amide 3 is an attractive CSA for NMR analysis of protected amines. It is readily prepared in a single step and combines practical resolution of diastereomeric complexes due to signal sharpness and effective signal separation. Crystallographic analysis shows that 3 forms a chiral cleft that can selectively bind one enantiomer of a substrate through hydrogen bonding, pi-pi stacking, and CH/pi interactions. The enantioselective complex formation causes strong upfield shifts in the H-1 NMR spectrum even in the presence of only 5 mol % of 3.
Novel, Tunable, and Efficient Chiral Bisdihydrobenzooxaphosphole Ligands for Asymmetric Hydrogenation
作者:Wenjun Tang、Bo Qu、Andrew G. Capacci、Sonia Rodriguez、Xudong Wei、Nizar Haddad、Bikashandarkoil Narayanan、Shengli Ma、Nelu Grinberg、Nathan K. Yee、Dhileep Krishnamurthy、Chris H. Senanayake
DOI:10.1021/ol9025815
日期:2010.1.1
A series of novel, efficient, air-stable, and tunable chiral bisdihydrobenzooxaphosphole ligands (BIBOPs) were developed for rhodium-catalyzed hydrogenations of various functionalized olefins such as alpha-arylenamides, alpha-(acylamino)acrylic acid derivatives, beta-(acylamino)acrylates, and dimethyl itaconate with excellent enantioselectivities (up to 99% ee) and reactivities (up to 2000 TON).