Eschenmoser-Tanabe

Fragmentation of a.fJ-Epoxy Hydrazones Eschenmoser-Tanabe ring cleavage... 

Eschenmoser Fragmentation (Eschenmoser-Tanabe Fragmentation / Ring Cleavage)... 

During modei studies for the synthesis of botrydiane sesquiterpene antibiotics, B.M. Trost and co-workers prepared a compiex 1,6-enyne precursor for transition metal catalyzed enyne metathesis reactions. The 1,6-enyne was prepared from a heavily substituted alkynal, which was synthesized via the Eschenmoser-Tanabe fragmentation of an epoxy ketone. The resulting alkynal was unstable, so it was immediately subjected to a Wittig oiefination to afford the desired 1,6-enyne. 

Eschenmoser-Tanabe fragmentation Formation of alkynals or alkynones from epoxy ketone hydrazones. 158... 

Related reactions Eschenmoser-Tanabe fragmentation, Wharton fragmentation ... 

Crabbe and Greene employed a similar approach in their synthesis of a Corey intermediate. The synthesis, depicted in Scheme 1.33, began by construction of cuprate 166 via a slightly different route. 3-Methyl cyclohexenone (180) was epoxidized and subjected to Eschenmoser-Tanabe fragmentation to give the acetylenic ketone 181. Reduction of ketone 181 to the alcohol and protection afforded 164, which had been previously converted to cuprate 166 by Corey. 

Erdmann (see Volhard-Erdmann Cyclization) Erlenmeyer-Plochl Azlactone and Amino Acid Synthesis Eschenmoser Coupling Reaction Eschenmoser Fragmentation Eschenmoser-Claisen Rearrangement Eschenmoser-Tanabe Fragmentation Eschweiler-Clarke Reaction Etard Reaction... 

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