Enyne Metathesis Using Chromium Carbene Complexes. Synthesis of Heterocycles from Enynes Using Chromium Carbene Complex

Watanuki, Susumu; Mori, Miwako

doi:10.1021/om00011a026

Cited by 31 publications

(15 citation statements)

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“…[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.…”

Section: Enyne Metathesismentioning

confidence: 98%

“…(The literature includes many examples of beneficial effect of ethylene and other cases where ethylene has no helpful effect on the reaction.) [3] (12) (13) (14) In early reports on the intramolecular, ring-closing metathesis, internal alkynes were used with great success. [16] After the Blechert report, synthetic applications turned to intermolecular metathesis, and here the benefits of internal alkynes were overshadowed by the problem of poor regiocontrol.…”

Section: Enyne Metathesismentioning

confidence: 99%

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Ruthenium vinyl carbene intermediates in enyne metathesis

Diver

2007

Coordination Chemistry Reviews

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This review provides an overview of ruthenium vinyl carbene reactivity as it relates to enyne metathesis. Methods for the synthesis of metathesis-active and metathesis-inactive complexes are also summarized. Some of the early hypotheses about vinyl carbene intermediates in enyne metatheses were tested in the arena of synthetic chemistry and subsequently led to mechanistic studies. In these two areas, studies from the author's labs are described. There are still many unresolved questions in enyne metathesis that trace back to vinyl carbene reactivity. Hopefully this review will stimulate further investigation into vinyl carbene reactivity which should further refine our understanding of catalytic enyne metathesis.

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Section: Enyne Metathesismentioning

confidence: 98%

Section: Enyne Metathesismentioning

confidence: 99%

Ruthenium vinyl carbene intermediates in enyne metathesis

Diver

2007

Coordination Chemistry Reviews

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“…Intramolecular annelations [16] of α,β-unsaturated Fischer carbene complexes, i.e. di-and triynyl complexes, and intermolecular cascade cycloadditions [17] of alkyl complexes with enynes, diynes etc. are well known.…”

Section: Resultsmentioning

confidence: 99%

From α,β‐Unsaturated Fischer Carbene Complexes to Highly Substituted 3‐Ethoxycyclopentadienes, Masked Cyclopentenones

Flynn

Schirmer

et al. 2004

Eur J Org Chem

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The β-amino-substituted α,β-unsaturated Fischer carbene complexes 3 are readily available by a four step one-pot procedure from terminal alkynes, chromium hexacarbonyl and secondary amines (24 examples with yields of 68−99% and 7 examples with yields of 26−63%). The formal [3+2] cycloadditions of complexes 3 with different alkynes including diynes and enynes performed in donor solvents such as pyridine or acetonitrile afforded highly substituted 5-(dialkylamino)-3-ethoxycyclopentadienes 7, generally in medium to excellent yields (25 examples with yields of 60−95% and 7 examples with yields of 18−53%). The steric and electronic effects of the substituents on the carbene complexes and the incorporated alkynes on the regio-and stereoselectivity of the ring-forming reaction have been elaborated. An interesting 1,5-or, more likely, 1,2-migration of the dimethylamino group was observed for 5-(dimethylamino)-3-ethoxycyclopentadienes with trimethylsilyl and iPr substituents at C-5. Attempted asymmetric syntheses of cyclopentadienes 7 from complexes 3 with chiral amino groups or substituents were only moderately successful. At a center of chirality in the secondary amino group, complexes of type 3 gave compounds 7 with diastereomeric excesses of, at best, 59% in yields of

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“…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.…”

Section: B Intramolecular Ring-closing Enyne Metathesismentioning

confidence: 99%

“…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).…”

Section: B Intramolecular Ring-closing Enyne Metathesismentioning

confidence: 99%