A Facile Entry into Benzo-/Naphtho-pyrano-indolizino-indole through Sequential Intramolecular 1,3-Dipolar Cycloaddition and Pictet-Spengler Cyclisation
An Efficient and Versatile Approach for the Immobilization of Carbene Precursorsvia Copper-Catalyzed [3+2]-Cycloaddition and their Catalytic Application
作者:Kirsten Zeitler、Ina Mager
DOI:10.1002/adsc.200700174
日期:2007.8.6
azide-functionalized support via copper-catalyzed 1,3-dipolarcycloaddition, which efficiently yields a rigid and robust 1,2,3-triazole linkage. The catalytic performance of the corresponding nucleophilic carbenes (NHCs) was examined in intramolecular Stetter reactions (chroman-4-one products) and organocatalytic redox esterifications (α,β-unsaturatedesters). The MeOPEG-immobilized organocatalysts are
The firstasymmetric intramolecular Stetter reaction is reported, using the chiral triazolium salt 1 as catalyst. Starting from the easily accessible 4-(2-formylphenoxy)but-2-enoates 2, this protocol opens up an enantioselective pathway to the benzo-annulated pyran-4-ones (chroman-4-ones) 3a–h with good yields and enantiomeric excesses of up to 74%.
An intramolecular Diels–Alder reaction involving fulvenes as 4π components—stereoselective synthesis of novel oxatricyclo[6.4.0.02,10] dodeca-2,11-diene ring system
作者:S Manikandan、M Shanmugasundaram、R Raghunathan
DOI:10.1016/s0040-4020(01)01174-7
日期:2002.1
Fulvenes acting as 4π components in an intramolecular [4+2] cycloaddition reaction leading to the formation of novel 6-oxatricyclo [6.4.0.02,10] dodeca-2,11-diene ring systems have been described. Importance of steric buttressing effect in promoting the reaction has been discussed.
Remarkable Differences in Reactivity between Cyanide and N‐Heterocyclic Carbene
<scp>s</scp>
in
<scp>Ring‐Closing</scp>
Reactions of 4‐(
<scp>2‐Formylphenoxy</scp>
)but‐2‐Enoate Derivatives
作者:Eunjoon Park、Jina Park、Cheol‐Hong Cheon
DOI:10.1002/bkcs.12146
日期:2021.3
A different reactivity between cyanide and NHC with 4‐(2‐formylphenoxy) but‐2‐enoate derivatives is described.