Chromium-Catalyzed Intramolecular Enyne Metathesis

Ruthenium vinyl carbene intermediates in enyne metathesis

“…[12] Shortly after the seminal report of catalytic ring closing enyne metathesis, chromium Fischer carbenes were employed by Mori and coworkers to form nitrogen heterocycles. [13][14][15] Though these reactions were substoichiometric or even stoichiometric in the chromium complexes, this paper elevated an interesting organometallic reaction to one that might prove useful in organic synthesis, where the presence of functional groups places great demands on chemoselection. Mori's papers stimulated interest in the reaction since heterofunctionality could be handled.…”

5.27 Ene–Yne Metathesis

“…After a decade, Mori's group applied the metathesis to challenging nitrogen heterocycle synthesis. [6][7][8] However, the real breakthrough came from alkene metathesis when the Grubbs group reported a well-defined, group VIII ruthenium carbene complex. 9 This led to a number of applications by Grubbs and Fu, which captured the attention of the synthetic community (ruthenium, 10 molybdenum 11 ).…”

Unique Metal‐Diyne, ‐Enyne, and ‐Enediyne Complexes: Part of the Remarkably Diverse World of Metal‐Alkyne Chemistry

“…The synthetic value of this reaction is enhanced by the fact that, in addition to being a means to an end in itself, the 1,3-diene systems thus formed are themselves versatile synthetic reagents that can undergo further selective transformations (e.g., cycloaddition reactions). The metathesis reaction can be catalyzed by metal carbenes or by low-valent transition metals (e.g., chromium, ruthenium, iridium, palladium, platinum, gold, and their salt complexes) (401,(410)(411)(412)(413)(414)(415)(416)(417)(418)(419)(420). Synthetic applications of enyne metathesis can be separated into three main areas: intramolecular (ring-closing) enyne metathesis; intermolecular (cross) enyne metathesis, and tandem enyne metathesis.…”

“…The catalytic enyne metathesis reaction was first discovered by Katz and Sivavec (421) (424,425), Fischer carbene complexes of chromium were shown to catalyze the enyne metathesis of 1,6-enynes in which the alkene terminus supports an alkoxy group (419,420). However, Grubbs' catalyst (426) was later found to be more broadly applicable (427,428).…”