A photoredox decarboxylative coupling of N-hydroxyphthalimide esters with aldimines is reported for synthesizing α-amino esters. A broad scope of alkyl radicals generated under visible light irradiation adds to glyoxylate aldimines in reliably good to excellent yields. Adding inorganic bases such as potassium carbonate significantly enhanced the yields by suppressing the umpolung side reaction. The
Indium-Mediated Addition of γ-Substituted Allylic Halides to N-Aryl α-Imino Esters: Diastereoselective Production of β,β′-Disubstituted α-Amino Acid Derivatives with Two Contiguous Stereocenters
作者:Nayyar Ahmad Aslam、Vadla Rajkumar、Chennakesava Reddy、Makoto Yasuda、Akio Baba、Srinivasarao Arulananda Babu
DOI:10.1002/ejoc.201200254
日期:2012.8
γ-substituted allylic halides to N-aryl (including N-PMP) α-imino- and N-acylhydrazono esters and highly diastereoselective tailoring of functionalized γ,δ-unsaturated β,β′-disubstituted N-aryl α-amino acid derivatives, bearing two contiguous stereocenters is reported. Further N-allylation of the resulting γ,δ-unsaturated β,β′-disubstituted N-aryl amino acid derivatives followed by ringclosingmetathesis (RCM)
Cooperative catalysis by carbenes and Lewis acids in a highly stereoselective route to γ-lactams
作者:Dustin E. A. Raup、Benoit Cardinal-David、Dane Holte、Karl A. Scheidt
DOI:10.1038/nchem.727
日期:2010.9
more catalytic cycles operate concurrently to achieve one overall transformation, has great potential in enhancing known reactivity and driving the development of new chemical reactions with high value. In this disclosure, a cooperative N-heterocyclic carbene/Lewis acid catalytic system promotes the addition of homoenolate equivalents to hydrazones, generating highly substituted γ-lactams in moderate
β-Carbon activation of saturated carboxylic esters through N-heterocyclic carbene organocatalysis
作者:Zhenqian Fu、Jianfeng Xu、Tingshun Zhu、Wendy Wen Yi Leong、Yonggui Robin Chi
DOI:10.1038/nchem.1710
日期:2013.10
The activation of the α-carbons of carboxylic esters and related carbonyl compounds to generate enolate equivalents as nucleophiles is one of the most powerful strategies in organic synthesis. We reasoned that the horizons of chemical synthesis could be greatly expanded if the typically inert β-carbons of saturated esters could be used as nucleophiles. However, despite the rather significant fundamental
the stereochemistry of HPA-12, an important ceramide-trafficking inhibitor that was discovered and synthesized and its stereochemistry determined in 2001, the synthesis and the stereochemistry were reinvestigated. A large-scale synthetic method for HPA-12 based on a Zn-catalyzed asymmetric Mannich-type reaction in water was developed. Single crystals of HPA-12 for X-ray crystallographic analysis were