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Archive for the ‘Zinc’ Category

Thiophenes from Simmons-Smith

Posted by naturalproductman on November 30, 2012

Kanchugarakoppal Rangappa and co-workers at the University of Mysore in India have reported in Tetrahedron Letters on the synthesis of thiophenes using a Simmons-Smith reagent.

thiophene

TL paper

Posted in Cascade Reactions, Copper, Methodology, Named Reagents, Simmons-Smith, Transition Metal, Zinc | Leave a Comment »

1,4-conjugate addition in water

Posted by naturalproductman on November 28, 2012

Bruce Lipshutz and co-workers have reported in JACS on a organocuprate Michael addition in WATER.

Cu

JACS paper

Posted in Cascade Reactions, Copper, Environmental, Methodology, Transition Metal, Zinc | Leave a Comment »

Cyclopropanol ring opening

Posted by naturalproductman on August 22, 2012

Jin Kun Cha and co-workers at Wayne State University have reported in ACIE on a ring opening of cyclopropanol using stoichiometric diethyl zinc.

sn2 prime

ACIE paper

Posted in Cascade Reactions, Methodology, Ring Opening, Sn2 prime, Transition Metal, Zinc | Leave a Comment »

Some [2+2] cycloaddition chemistry

Posted by naturalproductman on February 10, 2012

Tehshik Yoon and co-workers published in Organic Letters on a [2+2] photocycloaddition.

2+2

OL paper

Nessan Kerrigan and co-workers at Oakland University have reported in JACS on a [2+2] reaction between ketenes to form beta-lactones.

beta-lactones

JACS paper

At first look at Daniel Romo’s name I thought of Tony Romo and funny enough they’re both in Texas.  Here they report on a Mukaiyama Aldol lactonization to form beta-lactones.

2+2

JACS paper

Posted in Cascade Reactions, Cycloaddition, Light Mediated, Methodology, Mukaiyama, Named Reactions, Pericyclic reactions, Transition Metal, Zinc, [2+2] | Leave a Comment »

Pyridine synthesis

Posted by naturalproductman on December 5, 2011

Sang-gi Lee and co-workers have reported in Organic Letters on a synthesis of a substituted pyridine.

pyridine

OL paper

Posted in Blaise, Cascade Reactions, Methodology, Named Reactions, Transition Metal, Zinc | Leave a Comment »

Ketene cascade

Posted by naturalproductman on September 18, 2011

Anthony Barrett and co-workers at Imperial College have reported in Organic Letters on a cascade reaction that involves the formation of a ketene followed by trapping with an enamine to form pyridinones.

pyridinones

OL paper

Posted in Cascade Reactions, Claisen condensation, Diels-Alder, Methodology, Named Reactions, Transition Metal, Zinc | Leave a Comment »

Cobalt catalyzed Michael addition of alkyne to enone

Posted by naturalproductman on August 18, 2011

Tamio Hayashi and co-workers at Kyoto University have reported in Chem Comm on a cobalt catalyzed Michael addition of an alkyne onto an enone.

cobalt

Chem Comm paper

Posted in Asymmetric, Cobalt, Methodology, Michael, Named Reactions, Transition Metal, Zinc | Leave a Comment »

Alkyl zinc addition onto alkene

Posted by naturalproductman on July 11, 2011

Matthew Sigman and colleague at the University of Utah have reported in JACS on an anti-Markovnikov addition of an alkyl group onto an alkene using an alkyl zinc reagent.

zinc

JACS paper

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

Regioselective epoxide opening for lysergic acid

Posted by naturalproductman on June 10, 2011

Hiroaki Ohno and co-workers from Kyoto University have reported in JOC on their total synthesis of lysergic acid via a regioselective epoxide opening using a reducing agent.

epoxide

JOC paper

Posted in Alkaloids, Indoles, Methodology, Regioselective, Ring Opening, Transition Metal, Zinc | Leave a Comment »

Autocatalysis may be a rising field

Posted by naturalproductman on March 1, 2011

Carreira and co-workers have reported in ACIEE on an autocatalysis reaction.  Normally we think of an asymmetric reaction involving the substrate, reagent, and a catalyst with a chiral ligand.  In this case, they are adding a fourth realm:  the product itself and in enantiomerically pure form.  They are saying that the addition of the product which is in high ee would increase the overall enantioselectivity of this reaction.  I have some questions about this like:  wouldn’t the composition of the enantiomerically pure product you’re adding to the reaction contribute to the ee of the final reaction?

autocatalysis

ACIEE paper

Posted in Asymmetric, Methodology, Transition Metal, Zinc | Leave a Comment »

 
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