Asymmetric Epoxidation of α,β-Unsaturated Aldehydes in Aqueous Media Catalyzed by Resin-Supported Peptide- Containing Unnatural Amino Acids
作者:Kengo Akagawa、Kazuaki Kudo
DOI:10.1002/adsc.201000805
日期:2011.4.18
The enantio‐ and diastereoselective epoxidation of α,β‐unsaturated aldehydes in aqueousmedia was realized using a resin‐supported peptide catalyst. Introducing the hydrophobic and bulky unnaturalaminoacid 3‐(1‐pyrenyl)alanine into the peptide sequence was effective for enhancing the reaction rate and enantioselectivity.
A novel stereocontrolled synthesis of optically active α-furyl amines and α-furyl carbinols from α,β-aziridine and α,β-epoxy aldehydes using a one-pot aldol reaction–intramolecular enolcyclization is described.
The direct organocatalytic enantioselective epoxidation of α,β-unsaturated aldehydes with different peroxides is presented. Proline, chiral pyrrolidine derivatives, and amino acid-derived imidazolidinones catalyze the asymmetric epoxidation of α,β-unsaturated aldehydes. In particular, protected commercially available α,α-diphenyl- and α,α-di(β-naphthyl)-2-prolinols catalyze the asymmetric epoxidation
A supported version of N-(tert-butyl)phenylsulfinimidoyl chloride on a monolithic material is described, which can be incorporated into a flow chemical processing arrangement to oxidise a variety of substrates in both stoichiometric and catalytic processes to yield products in high yields and in high purity after in-line workup.
Enantioselective organocatalytic epoxidation using hypervalent iodine reagents
作者:Sandra Lee、David W.C. MacMillan
DOI:10.1016/j.tet.2006.07.055
日期:2006.12
A rare example of a hypervalentiodine reagent participating in a 1,4-heteroconjugate addition reaction is reported for the organocatalytic, asymmetric epoxidation of α,β-unsaturated aldehydes using imidazolidinone catalyst 1. Development of an ‘internal syringe pump’ effect via the slow release of iodosobenzene from an iminoiodinane source provides high levels of reaction efficiency and enantiomeric
据报道,使用咪唑烷酮催化剂1可以使α,β-不饱和醛发生有机催化,不对称环氧化,这是参与1,4-杂合物加成反应的高价碘试剂的一个罕见例子。通过从亚碘碘烷源缓慢释放碘代苯来开发“内部注射泵”效应,可在缺电子烯烃的不对称环氧化中提供高水平的反应效率和对映体控制。进行了15 N NMR研究,以阐明在原型氧化剂存在下导致催化剂耗竭的反应途径。这些NMR研究也为亚氨基碘烷作为内部缓释氧化剂的应用提供了机理基础,以规避这些催化剂的消耗途径。