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Archive for the ‘Conjugate Additions’ Category

Vitamin D analog

Posted by naturalproductman on May 4, 2011

Atsushi Kittaka and co-workers from Teikyo University have reported in Organic Letters on a synthesis of a vitamin D analog.

vitamin D

OL paper

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Posted in Conjugate Additions, Copper, Methodology, Transition Metal | Leave a Comment »

Water displaces an allylic chloride, asymmetrically

Posted by naturalproductman on April 22, 2011

Kiyotaka Onitsuka and colleague at Osaka University have reported in ACIEE on a ruthenium catalyzed Sn2 prime reaction where water displaces a chloride.
ruthenium

ACIEE paper

Posted in Asymmetric, Conjugate Additions, Methodology, Ruthenium, Sn2 prime, Transition Metal | Leave a Comment »

Palladium-catalyzed conjugate addition of boronic acids

Posted by naturalproductman on April 18, 2011

Brian Stoltz and colleagues have reported in JACS on a palladium catalyzed conjugate addition of boronic acids onto cyclo- penten-, hexen-, and heptenones.  Normally people publish this kind of chemistry with rhodium.

boronic acid

JACS paper

Posted in Conjugate Additions, cross coupling, Methodology, Palladium, Transition Metal | Leave a Comment »

Cobalt Catalyzed Conjugate Addition

Posted by naturalproductman on April 18, 2011

Chien-Hong Cheng and co-workers at the National Tsing Hua University in Taiwan have published in JACS on a cobalt catalyzed alkyne addition onto an enone.

Michael

JACS paper

Posted in Cobalt, Conjugate Additions, Methodology, Transition Metal | Leave a Comment »

Nucleophilic Dearomatization

Posted by naturalproductman on April 12, 2011

Jonathan Clayden and colleague from the University of Manchester have reported in Tetrahedron Letters on a dearomatization of an aryloxazoline using an organolithium reagent.

dearomatization

TL paper

Posted in Conjugate Additions, Dearomatization, Methodology | Leave a Comment »

Englerin A Synthesis

Posted by naturalproductman on April 8, 2011

William Chain and co-workers at the University of Hawaii have reported in JACS on a total synthesis of englerin A where they took advantage of some radical chemistry (SmI2-mediated) to form that 7 membered ring.
englerin A

JACS paper

Posted in Asymmetric, Conjugate Additions, Methodology, Radical Chemistry, Sesquiterpenes, Total Synthesis | Leave a Comment »

Nucleophilicity: Alpha vs. Beta Position

Posted by naturalproductman on March 18, 2011

Zhi-Xiang Wang and co-workers at the Chinese Academy of Sciences have reported in JOC on a Morita Baylis Hilman type reaction using either trimethyl phosphine or an NHC catalyst.

NHC

 

JOC paper

Posted in Cascade Reactions, Computational, Conjugate Additions, Mechanistic, Methodology, Morita-Baylis-Hillman, Named Reactions, Organocatalytic | Leave a Comment »

Oxazolones with allylic carbonates

Posted by naturalproductman on March 12, 2011

Min Shi and co-workers at the Chinese Academy of Sciences have reported in Organic and Biomolecular Chemistry on a bifunctional organocatalyst that makes use of a nucleophilic phosphine and a thiourea moiety to add oxazolones to allylic carbonates that look like Morita Baylis Hillman adducts.  The oxazolones can in turn be opened under acidic conditions.

MBH

OBC paper

Posted in Conjugate Additions, Methodology, Organocatalytic | Leave a Comment »

Ruthenium Coupling

Posted by naturalproductman on March 3, 2011

Masafumi Hirano and colleagues at Tokyo University of Agriculture and Technology have reported in Organometallics on a ruthenium catalyzed coupling between a methacrylate and 2,5-dihydrofuran.

ruthenium

 

OM paper

Posted in Conjugate Additions, cross coupling, Methodology, Ruthenium, Transition Metal | Leave a Comment »

Exocyclic Methylenes

Posted by naturalproductman on November 28, 2010

Tomasz Janecki and co-workers have published in Synlett on a nice way to make subsituted 3-methylidene-chroman-2-ones (ie:  exocyclic methylenes) via 1,4-Grignard addition folowed by Wittig.

exocyclic methylene

Synlett paper

Posted in Conjugate Additions, Horner-Wadsworth-Emmons, Methodology, Named Reagents | Leave a Comment »