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Archive for the ‘Ylides’ Category

Pyrans from Pyridiniums

Posted by naturalproductman on August 3, 2010

Norbert De Kimpe and co-workers at Ghent University have published in Tetrahedron on the use of pyridinium ylides to form a pyran ring in naphthoquinones.

naphthoquinones


Tetrahedron paper

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

Bengamide Synthesis

Posted by naturalproductman on July 22, 2010

Francisco Sarabia and co-workers at the University of Maraga have published on the use of chiral sulfur ylides to form epoxides by condensing them with an aldehyde. They used this methodology to synthesize bengamide E.

sulfur

JOC paper

Posted in Alkaloids, Cascade Reactions, Methodology, Total Synthesis, Ylides | Leave a Comment »

Carbonyl Ylide Approach to Seven Membered Rings

Posted by naturalproductman on June 29, 2010

Martin Maier and co-workers at the Universitat Tubingen have published in Organic Letters on a carbonyl ylide cycloaddition with allyl propiolate to synthesize a guaianolide 5,7-bicyclic ring system.

Carbonyl Ylide

OL paper

Posted in Cascade Reactions, Cycloaddition, Methodology, Pericyclic reactions, Rhodium, Transition Metal, Ylides | Leave a Comment »

An Interesting Structure

Posted by naturalproductman on May 12, 2010

Alan Aitken and co-workers at the University of Saint Andrews in the UK have recently published in European JOC on a reaction that involves two equivalents of an ylide reacting with an acid chloride to lead to a bis-triphenylphosphino-propenidyl intermediate.

structure

European JOC paper

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

Cyclopropanation with Nitrogen Ylides

Posted by naturalproductman on May 7, 2010

Javier Perez-Castells and co-workers at Universidad San Pablo-CEU have recently reported in Tetrahedron Letters on a cyclopropanation reaction of an alpha-haloketone compound onto an enone.

cyclopropanation

TL paper

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

Platinum Containing Pyrylium Cycloadditions

Posted by naturalproductman on April 16, 2010

Chang Ho Oh and co-workers at Hanyang University have recently reported in Chemical Communications on generation of pyrylium ions from an aldehyde containing an alkyne in the presence of platinum.  These ylides that are formed may undergo cyclizations with alkenes to form polycyclic compounds from linear starting materials.

ylide

Chem Comm paper

Posted in Cascade Reactions, Cycloaddition, Methodology, Platinum, Transition Metal, Ylides | Leave a Comment »

Vinyl Pyridinium Ylide Cyclization

Posted by naturalproductman on April 7, 2010

Ponnusamy Shanmugam and co-workers have recently published in Organic Letters on a pyridinium ylide formation that cyclizes to form spirocyclic centers.

pyridinium

OL paper

Posted in Methodology, Morita-Baylis-Hillman, Named Reactions, Pericyclic reactions, Spirocycles, Ylides | Leave a Comment »

Carbonyl Ylides

Posted by naturalproductman on March 23, 2010

Hiroyuki Suga and co-workers at Shinshu University have recently reported in Tetrahedron on a metallocarbenoid approach to synthesizing 6,5-bicyclic ring systems containing a tetrahydrofuran.

carbonyl

Tetrahedron paper

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

Aza-Wittig and Aza-retro-Claisen

Posted by naturalproductman on March 10, 2010

Robert Boeckman and co-workers at the University of Rochester have recently published in Organic Letters on an aza-Wittig/aza-retro-Claisen reaction to yield heterocyclic nitrogen containing compounds.

aza

OL paper

Posted in Cascade Reactions, Claisen rearrangement, Mechanistic, Methodology, Named Reactions, Wittig, Ylides | Leave a Comment »

Azo-Methine Ylide Cascade

Posted by naturalproductman on March 1, 2010

Guillame Belanger and co-workers at Universite de Sherbrooke in Canada have recently published in Organic Letters on a cascade cyclization that requires an formamide tethered by an allyl silane, which generates an azomethine ylide, which in turn undergoes a cyclization process to yield a bicyclic compound.

cascade
OL paper

Posted in Cascade Reactions, Cycloaddition, Methodology, Pericyclic reactions, Ring forming, Ylides | Leave a Comment »