Expanded scope for the iridium-catalyzed asymmetric isomerization of primary allylic alcohols using readily accessible second-generation catalysts
作者:Luca Mantilli、Clément Mazet
DOI:10.1039/b920342g
日期:——
A second generation of chiral (P,N)-iridium catalysts--readily accessible from inexpensive L-serine--displays expanded scope for the asymmetricisomerization of primaryallylicalcohols.
Synthesis and Application of ChiralN-Heterocyclic Carbene–Oxazoline Ligands: Iridium-Catalyzed Enantioselective Hydrogenation
作者:Steve Nanchen、Andreas Pfaltz
DOI:10.1002/chem.200501500
日期:2006.6.2
one compound from each family was characterized by X-ray structure analysis. The two libraries of iridium complexes were successfully tested in the asymmetric hydrogenation of unfunctionalized and functionalized olefins. Enantioselectivities of up to 90 % ee were obtained with trans-alpha-methylstilbene. Upon complexation of imidazolium salt 15 p with R(1) = phenyl, C-H bond activation of the phenyl
Modular Phosphite–Oxazoline/Oxazine Ligand Library for Asymmetric Pd-Catalyzed Allylic Substitution Reactions: Scope and Limitations—Origin of Enantioselectivity
作者:Montserrat Diéguez、Oscar Pàmies
DOI:10.1002/chem.200701636
日期:2008.4.18
A library of phosphite-oxazoline/oxazine ligands L1-L15 a-h has been synthesized and screened in the Pd-catalyzed allylic substitution reactions of several substrate types. These series of ligands can be prepared efficiently from easily accessible hydroxyl amino acid derivatives. Their modular nature enables the substituents/configurations in the oxazoline/oxazine moiety, alkyl backbone chain and in
Oxazoline derivatives were mainly obtained from the O-tosyl-N-acyl-β-hydroxy amino acid peptides by β-elimination reaction. Dehydroalanine or hydantoin derivatives were isolated when the urethane type acyl groups were used.
Synthesis and Biological Evaluation of Structurally Highly Modified Analogues of the Antimitotic Natural Product Curacin A
作者:Peter Wipf、Jonathan T. Reeves、Raghavan Balachandran、Billy W. Day
DOI:10.1021/jm0105171
日期:2002.4.1
analysis of synthetic analogues of curacin A revealed the lack of activity of traditional heterocyclic replacements of the thiazoline ring or cyclopropyl analogues of the core diene segment. The significance of the C(3)-C(4)-(Z)-alkene geometry was established, and a novel oxime analogue was designed that displays biological properties that are a close match of the naturalproduct lead. The much less