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Archive for the ‘Methodology’ Category

[4+2] with diazo esters

Posted by naturalproductman on February 8, 2016

Michael Doyle and co-workers at UT San Antonio have reported in JACS on the first Diels-Alder example involving a diazoester dienophile.

DOYLE jacs 2016

JACS paper

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

Gold catalyzed photoredox chemistry

Posted by naturalproductman on February 3, 2016

Stephen Hashmi and co-workers have reported in ACIE on the use of a gold dimer catalyst with a diphenylphosphinomethane ligand to effect a difluoroalkylation reaction.

hashmi ACIE 2016.gif

ACIE paper

Posted in Gold, Light Mediated, Methodology, Radical Chemistry, Transition Metal | Leave a Comment »

Tubulysin syntheses

Posted by naturalproductman on February 2, 2016

KC Nicolaou and co-workers have reported in JACS on the synthesis of tubulysin and some analogs. There are some interesting propellane analogs that reminded me of the recent Baran paper in Science that involved some strain-release amination reactions – the Baran paper involved the use of strained rings that would react with free amines to form new C-N bonds. I like the analogy in this photograph, where the two co-first authors of the paper (holding hands) represent the “strained ring” and the “amine” is Phil Baran pouring a flask to break the strain.

JACS paper

One pot C-N bond formation (Science paper):

RING STRAIN RELEASE 02.02.2016.gif

Posted in Methodology, Strained Rings, Total Synthesis | Leave a Comment »

Chiral phosphoric acid for allenamides with ketones

Posted by naturalproductman on January 29, 2016

Dean Toste and colleague have reported in Chemical Science on the use of a chiral phosphoric acid catalyst to react allenamides with ketones. I guess the papers published in Chemical Science in 2015 and 2016 are all open access.

 

Chemical Science paper

Posted in Allenes, Methodology, Organocatalytic | Leave a Comment »

Jungermannenones B and C synthesis

Posted by naturalproductman on January 29, 2016

Xiaoguang Lei and co-workers from Peking University have reported in ACIE on the synthesis of jungermannenones B and C.

 

ACIE paper

Posted in Cascade Reactions, Methodology, Radical Chemistry, Total Synthesis | Leave a Comment »

3 Diels-Alder reactions in 1 go

Posted by naturalproductman on January 29, 2016

Michael Sherburn and co-workers from the Australian National University reported in JOC on a Diels-Alder cascade sequence.

DIELS ALDER CASCADE 01.29.2016.gif

JOC paper

 

Here’s an interesting related ACIE paper by the same group.

Posted in Cascade Reactions, Diels-Alder, Methodology, Named Reactions | Leave a Comment »

2 Reagents, 2 mechanisms, same product

Posted by naturalproductman on January 28, 2016

Srinivasan Chandrasekaran and colleague at the Indian Institute of Science have reported in Tetrahedron on a mechanistically interesting transformation involving a geminal aminooxygenation of a vinyl arene. Two different reaction conditions were identified: one with m-CPBA, the other with a hypervalent iodine reagent. The former underwent a deuterium shift on the gem-dideuterated-styrene starting material and the latter does not.

01.28.2016 naturalproductman.gif

Tetrahedron paper

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

Expect the unexpected – allylic alcohols from epoxides

Posted by naturalproductman on January 27, 2016

Margaret Brimble and co-workers from the University of Auckland have reported in Organic Letters on a cobalt-catalyzed conversion of an epoxide to an allylic alcohol using the Corey-Chaykovsky reagent.

 

OL paper

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

Alkyne hydrothiolation with Wilkinson’s catalyst

Posted by naturalproductman on January 27, 2016

Jennifer Love and co-workers from the University of British Columbia reported in Organic Letters on the use of Wilkinson’s catalyst to perform a hydrothiolation reaction across an alkyne to synthesize K777, a cysteine protease inhibitor.

 

OL paper

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

Fusarisetin A synthesis

Posted by naturalproductman on January 27, 2016

Yandong Zhang and co-workers at Xiamen University have reported in Organic Letters on a synthesis of fusarisetin A using a one pot intramolecular Diels-Alder/Mukaiyama aldol reaction cascade sequence.

OL paper

Posted in Cascade Reactions, Diels-Alder, Named Reactions, One pot, Total Synthesis | Leave a Comment »

 
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