Fe-Catalyzed Allylic C–C-Bond Activation: Vinylcyclopropanes As Versatile a1,a3,d5-Synthons in Traceless Allylic Substitutions and [3 + 2]-Cycloadditions
作者:André P. Dieskau、Michael S. Holzwarth、Bernd Plietker
DOI:10.1021/ja300294a
日期:2012.3.21
The low-valent iron complex Bu(4)N[Fe(CO)(3)(NO)] (TBAFe) catalyzes the allylic C-C-bond activation of electron-poor vinyl cyclopropanes to generate syntheticallyuseful a1,a3,d5-synthons which are prone to undergo multiple consecutive reactions. The versatility of this approach is demonstrated by a traceless allylic substitution and a formal [3 + 2] cycloaddition to give either functionalized acyclic
Diastereoselective Synthesis of Functionalized 5‐Amino‐3,4‐Dihydro‐2
<i>H</i>
‐Pyrrole‐2‐Carboxylic Acid Esters: One‐Pot Approach Using Commercially Available Compounds and Benign Solvents
A novel three‐step four‐transformation approach to highly functionalized 5‐amino‐3,4‐dihydro‐2H‐pyrrole‐2‐carboxylic acid esters, starting from commercially available phenylsulfonylacetonitrile, aldehydes, and N‐(diphenylmethylene)glycine tert‐butyl ester, was developed. The one‐pot strategy delivered this class of amidines bearing, for the first time, three contiguous stereocenters, in good to high
Reactions of vinyl sulfone with α-diazo-β-ketosulfone and Bestmann–Ohira reagent for the regioselective synthesis of highly functionalized pyrazoles
作者:Rahul Kumar、Deepa Nair、Irishi N.N. Namboothiri
DOI:10.1016/j.tet.2014.01.022
日期:2014.3
The 1,3-dipolarcycloaddition of diazomethylsulfone anion, generated in situ from α-diazo-β-ketosulfone, with vinyl sulfone proceeds in a regioselective manner to provide sulfonylpyrazoles. Similar reaction of diazomethylphosphonate anion, derived from Bestmann–Ohira reagent, with vinyl sulfone leads to phosphonylpyrazoles. The sulfonyl group of vinyl sulfone undergoes chemoselective elimination in
has been developed toward a range of carbocycles. The key success is based on the use of a batch of newly designed cyclic carbonates as substrates that can provide carbon–carbon zwitterion intermediate under palladium catalysis. The kinetics of the reactions are controllable toward either strained seven- or thermodynamically more favored five-membered carbocycles. The release of this chemistry will
In this paper, a simple and environment-friendly protocol was developed for the synthesis of arylsulfonyl 4H-pyrans via L-proline-catalyzed one-pot two-step reaction of aromatic aldehyde with phenylsulphonyl acetonitrile and dimedone under ball-milling conditions. Environmental acceptability, wide substrate scope, low cost and operational simplicity are the key features of this method.