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Archive for the ‘Transition Metal’ Category

Reactions involving transition metals

Rhodium cascade

Posted by naturalproductman on July 16, 2014

Richmond Sarpong and co-workers have reported in ACIE on a rhodium catalyzed cascade reaction involving an aza-Cope rearrangement.

Cope

ACIE paper

Posted in Aza-Cope rearrangement, Cascade Reactions, Methodology, Named Reactions, Rhodium, Transition Metal | Leave a Comment »

Indole alkaloid synthesis

Posted by naturalproductman on July 15, 2014

Corey Stephenson and colleague at the University of Michigan have reported in JACS on the synthesis of pseudotabersonine. A mental roadblock for me was when I was looking at the paper, I was trying to find the structure of catalyst 5, which was the iridium catalyst used for a ring opening reaction, but just found the number 5 in the scheme. Within the text of the paper however it says Ir(dF(CF3)ppy)2(dtbbpy)PF6, which was cited with a Sigma Aldrich catalog number.

 

photoredox

JACS paper

Posted in Alkaloids, Indoles, Iridium, Light Mediated, Methodology, Transition Metal | Leave a Comment »

Rh-catalyzed cycloisomerization

Posted by naturalproductman on June 7, 2014

Chisato Mukai and co-workers from Kanazawa University have reported in ACIE on a rhodium catalyzed cycloisomerization.
rhodium
 

ACIE paper

Posted in Allenes, Methodology, Rhodium, Transition Metal | Leave a Comment »

Dehydrogenation with iron

Posted by naturalproductman on June 7, 2014

William Jones and co-workers from the University of Rochester have reported in JACS on an iron catalyzed dehydrogenation.

dehydrogenation

JACS paper

Posted in Iron, Methodology, Transition Metal | Leave a Comment »

Pd-catalyzed C-N bond formation

Posted by naturalproductman on June 5, 2014

Matthew Gaunt and co-workers from the University of Cambridge have reported in Nature on a palladium catalyzed intramolecular C-N bond formation from C-H bonds. I am reminded of the ACIE paper from Frances Arnold’s group at Caltech where they used a P450 mutant to do a similar reaction.

 

Nature paper

Posted in C-H activation, Methodology, Palladium, Transition Metal | Leave a Comment »

[5+2] with rhodium

Posted by naturalproductman on May 14, 2014

Paul Wender and co-workers have reported in Organic Letters on a rhodium catalyzed [5+2] reaction.

propargyl

OL paper

Posted in Cascade Reactions, Methodology, Rhodium, Transition Metal | Leave a Comment »

Macrolactonization towards neopeltolide

Posted by naturalproductman on May 13, 2014

Mingji Dai and co-workers from Purdue have reported in ACIE on alkoxycarbonylative macrocyclization.

Pd

ACIE paper

Posted in Macrolides, Methodology, Palladium, Transition Metal | Leave a Comment »

Copper catalyzed [3+2] mechanism

Posted by naturalproductman on May 6, 2014

When I saw the graphical abstract of this paper, the first thing that came to mind was Michael Kerr at the University of Western Ontario, but this paper was from Yong Tang’s group in SIOC in collaboration with Kendall Houk’s computational group to study the mechanism of this [3+2] reaction. They used the LANL2DZ basis set in this paper. Great to hear.

copper

JACS paper

Posted in Cascade Reactions, Computational, Copper, DFT, Methodology, Transition Metal | Leave a Comment »

Polyene cyclization with titanocene

Posted by naturalproductman on May 6, 2014

Juan Cuerva and co-workers from the University of Granada in Spain have reported in JACS on a titanocene mediated polyolefin cyclization reaction that studied with Gaussian calculations. The basis set used to approximate the titanocene catalyst was 6-31G*. From my little knowledge of Gaussian, when using QM calculations to study a reaction mechanism, you need two things: 1) the basis set and 2) the method. The basis set is the linear combination of a set of functions used to approximate the molecular orbitals. There are many kinds of basis sets that can be used for Gaussian. In my experience with transition metals however, I was unable to use the 6-31G* basis set because the transition metals have more complicated molecular orbitals since they have d-orbitals. I had to use the Los Alamos basis set: LANL2Dz. I eventually gave up on my time with Gaussian because I just kept running into problems and eventually had to focus my efforts into experimental work. But hopefully one day I can go back to this stuff again. Afterall, it helps us understand the reaction mechanisms better.

titanocene

JACS paper

Posted in Cascade Reactions, Computational, DFT, Methodology, Titanium, Transition Metal | Leave a Comment »

Silylation of C-H bonds

Posted by naturalproductman on May 6, 2014

I like this silylation of a C-H bond using an iridium catalyst. Very interesting from the lab of John Hartwig at Berkeley.

Ir

JACS paper

Posted in Asymmetric, C-H activation, Iridium, Methodology, Transition Metal | Leave a Comment »

 
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