Catalytic asymmetric cycloaddition of unsymmetrical EWG-activated alkenes to fully substituted pyrrolidines bearing three different carbonyl groups

2019 ◽  
Vol 55 (95) ◽  
pp. 14363-14366
Author(s):  
Shi-Lu Wu ◽  
Ning Li ◽  
Guan-Wu Yin ◽  
Zheng Xu ◽  
Fei Ye ◽  
...  
Keyword(s):  
Carbonyl Groups ◽  
Silver Catalysis ◽  
Catalytic Asymmetric

A unique 1,3-dipolar [3+2] cycloaddition of alkyl 4-oxo-4-arylbut-2-enoates bearing two different electron-withdrawing groups could be completed easily via silver catalysis in good yields and enantioselectivity.

Chemical and orientational imaging of polymeric samples

1994 ◽  
Vol 52 ◽  
pp. 68-69
Author(s):  
H. Ade ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Carbonyl Groups ◽  
Aromatic Rings ◽  
Edge Structure ◽  
X Ray ◽  
Scanning Transmission ◽  
Polymeric Samples ◽  
X Ray Absorption

We have used the Scanning Transmission X-ray Microscope at beamline X1A (X1-STXM) at Brookhaven National Laboratory (BNL) to acquire high resolution, chemical and orientation sensitive images of polymeric samples as well as point spectra from 0.1 μm areas. This sensitivity is achieved by exploiting the X-ray Absorption Near Edge Structure (XANES) of the carbon K edge. One of the most illustrative example of the chemical sensitivity achievable is provided by images of a polycarbonate/pol(ethylene terephthalate) (70/30 PC/PET) blend. Contrast reversal at high overall contrast is observed between images acquired at 285.36 and 285.69 eV (Fig. 1). Contrast in these images is achieved by exploring subtle differences between resonances associated with the π bonds (sp hybridization) of the aromatic groups of each polymer. PET has a split peak associated with these aromatic groups, due to the proximity of its carbonyl groups to its aromatic rings, whereas PC has only a single peak.

Tandem Carbon-Radical Peroxidation−Addition to Carbonyl Groups Reaction. A New Synthesis of Steroidal β-Peroxy Lactones

1996 ◽  
Vol 61 (26) ◽  
pp. 9635-9635
Author(s):  
Alicia Boto ◽  
Rosendo Hernández ◽  
Ernesto Suárez ◽  
Carmen Betancor ◽  
María S. Rodríguez
Keyword(s):  
Carbonyl Groups ◽  
New Synthesis

A comment on the effect of carbonyl groups - on the light-induced reversion of groundwood pulp

1990 ◽  
Vol 5 (4) ◽  
pp. 159-160 ◽  
Author(s):  
Monica Ek ◽  
Helena Lennholm ◽  
Tommy Iversen
Keyword(s):  
Carbonyl Groups
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