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Archive for the ‘Mechanistic’ Category

Rearrange to more complexity

Posted by naturalproductman on July 27, 2014

Paul Hergenrother and co-workers from UIUC have reported in ACIE on an interesting rearrangement to form fenestrane ring systems.

cyclopropane

ACIE paper

Posted in Antibiotics, Cascade Reactions, Mechanistic, Methodology | Leave a Comment »

Electrocyclic ring opening to ketonitrones

Posted by naturalproductman on July 27, 2014

Masahiro Terada and co-workers from Tohoku University have reported in Organic Letters on a copper-catalyzed rearrangement to form alpha,beta-unsaturated ketonitrones.

nitrone

OL paper

Posted in Cascade Reactions, Copper, Electrocyclization, Mechanistic, Methodology, Pericyclic reactions, Transition Metal | Leave a Comment »

Ireland Claisen/Cope rearrangement

Posted by naturalproductman on June 30, 2014

James Leighton and co-workers reported in JACS on a mechanistic study of a tandem Ireland Claisen/Cope rearrangement reaction to form some polycyclic rings.

oxy Cope

JACS paper

Posted in Cascade Reactions, Claisen rearrangement, Cope rearrangement, Mechanistic, Methodology, Named Reactions, oxy-Cope rearrangement | Leave a Comment »

Syn-elimination

Posted by naturalproductman on May 14, 2014

Cristina de Meo and co-workers from Southern Illinois University reported in Organic Letters on a thiosialoside elimination of a thiophenol group, occuring by syn-elimination.

syn

OL paper

Posted in Half-chair, Isotope effects, Mechanistic | 1 Comment »

Alcohol to carboxylic acid by an enzyme

Posted by naturalproductman on May 7, 2014

Marco Fraaije and co-workers from the University of Groningen in the Netherlands have reported in ACIE on an enzyme catalyzed oxidation of an alcohol to carboxylic acid.

aldehyde

They did a mechanistic study, which caught my attention. They wanted to test if the carboxylic acid arises from the gem-diol of the aldehyde intermediate or directly from the aldehyde. The experiment was run under 18O-labeled water with 4-nitrobenzaldehyde. They state that if the reaction is spontaneous then the aldehyde will directly give the carboxylic acid with no 18O incorporated in the product, but if it is from the gem-diol, you will have 18O-atoms.

I have a problem with this part because the reaction can still come from the aldehyde if the carboxylic acid had an 18O-atom. The way this would occur is that the aldehyde can get hydrated to the gem-diol then it would be in equilibrium with the aldehyde and give back the aldehyde but this time it has an 18O-atom (STEP 2 product of below). This aldehyde, if oxidized by the enzyme, would yield the carboxylic acid with 18O-atom.

GIF RED
Anyway, interesting paper.
ACIE paper

Posted in Enzymatic, Mechanistic, Methodology | Leave a Comment »

Oxazoles to pyridines

Posted by naturalproductman on May 7, 2013

Pierre Yves-Renard and co-workers from CNRS have reported in Organic Letters on an interesting synthesis of pyridines.

pyridines

OL paper

Posted in Cascade Reactions, Mechanistic, Methodology | Leave a Comment »

Endoperoxide rearrangement

Posted by naturalproductman on May 7, 2013

Ihsan Erden and co-workers at SFSU have reported in Tetrahedron on an endoperoxide rearrangement.

rearrangement

Tetrahedron paper

Posted in Mechanistic, Methodology | Leave a Comment »

Asymmetric epoxidation

Posted by naturalproductman on April 19, 2013

Benjamin List and co-workers have reported in JACS on their studies of cinchona alkaloid catalyzed asymmetric epoxidation of activated olefins.

cinchona

JACS paper

Posted in Asymmetric, Computational, DFT, ESI, Mass Spectrometry, Mechanistic, Methodology, Organocatalytic | Leave a Comment »

Garuganin and garugamblin syntheses

Posted by naturalproductman on March 20, 2013

Chris Beaudry and co-workers at Oregon State have reported in JOC on some syntheses of diaryl heptanoids.

heptanoids

JOC paper

Posted in Asymmetric, Heptanoids, Mechanistic, Methodology, Structural Reassignment, Total Synthesis | Leave a Comment »

Iron catalyzed [2+2]

Posted by naturalproductman on March 15, 2013

Paul Chirik and co-workers from Princeton have reported in JACS on a mechanistic study of an iron catalyzed [2+2].

iron

JACS paper

Posted in Cascade Reactions, Mechanistic, Methodology | Leave a Comment »

 
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