Photolytic cleavage and isomerization reactions of (1-.sigma.,4-6-.eta.3-organo)tricarbonyliron complexes involving an (.eta.4-diene)(.eta.2-olefin)Fe(CO)2 intermediate. Quantum yields and mechanistic studies

Akiyama, T.; Grevels, Friedrich‐Wilhelm; Reuvers, Johannes G. A.; Ritterskamp, P.

doi:10.1021/om00073a030

Cited by 15 publications

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“…It could occur by decomposition of C , D , or E , which would draw F into the isomerization manifold ( C − E ) or by some other uncharacterized mechanism. The yield of F is also reduced by extended photolysis at 0 °C; this decomposition is likewise accompanied by isomerization of the α,β-ester to the other isomers probably by a mechanism other than that in Scheme ; this may involve photolytic dissociation of a CO group from F …”

Section: Discussionmentioning

confidence: 99%

Iron Carbonyl-Promoted Isomerization of Olefin Esters to Their α,β-Unsaturated Esters: Methyl Oleate and Other Examples

Shih

Angelici

1996

J. Org. Chem.

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Ultraviolet photolysis of stoichiometric amounts of methyl oleate and Fe(CO)(5) in hexanes solvent at 0 degrees C gives Fe(CO)(3)(eta(4)-alpha,beta-ester) in which the alpha,beta-unsaturated ester isomer of methyl oleate is stabilized by eta(4)-oxadiene pi coordination of the olefin and ester carbonyl groups to the Fe(CO)(3) unit. Treatment of the Fe(CO)(3)(eta(4)-alpha,beta-ester) with pyridine or CO liberates the free alpha,beta-ester, methyl octadec-trans-2-enoate, in 70% yield. The Fe(CO)(3) unit both catalyzes the olefin isomerization and stabilizes the alpha,beta-unsaturated ester, which results in the formation of the alpha,beta-ester in a yield far above that (3.5%) observed for simple catalyzed methyl oleate isomerization. The much smaller olefin esters, methyl 3-butenoate and ethyl 4-methyl-4-pentenoate, are isomerized under the same conditions to their alpha,beta-unsaturated esters in 94 and 90% yields, respectively. The effects of reaction conditions on the yield, the use of Fe(CO)(3)(cis-cyclooctene)(2) as a nonphotolytic catalyst, and the mechanism of this useful synthetic process are discussed.

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Section: Discussionmentioning

confidence: 99%

Iron Carbonyl-Promoted Isomerization of Olefin Esters to Their α,β-Unsaturated Esters: Methyl Oleate and Other Examples

Shih

Angelici

1996

J. Org. Chem.

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Of Iron, Ruthenium and Osmium

Abrahamson¹

1986

Inorganic Reactions and Methods

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Carbonyleisen‐assistierte Verknüpfung von Cyclopolyenen mit Acrylsäuremethylester

1985

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die gleiche n i d~-C~B~-S t r u k t~r~'~~ vor wie fur das Decaethy l-Derivat" l.Bei der Dimerisierung eines aquimolaren Gemischs der 2,3,4-Triethyl-1,5-dimethyl-und Pentaethyl-1,5-dicarbacloso-pentaborane(5) rnit Kalium und lod erhalt man drei gaschromatographisch trennbare'I4l C4B6-Carbaborane (HSC2)4C4B6(CZH5)6 (404)"'l. Bei der gaschromatographischen Trennung[I4] tritt wegen der thermischen Aquilibrierung der vier Geriist-C-Atome nur ein ,,gemischtes" Dimer auf. Ein Alkylmethantriyl-Austausch an den Bor-Atomen 1aBt sich durch das Ergebnis der Mischdimerisation aus-schlieRen.3 ist wie das Decaethyl-Derivatr'l bis ~~3 0 0°C stabil. Im Gegensatz zu 2 reagiert 3 bei ==2O"C nicht mit Sauerstoff.Von Ethanol wird 3 bei = 80°C bis zu Ethyl-ethoxy-boranen (S"B=53.7,31.1) abgebaut. 3 nimmt bei 20°C in THF Kalium auf: rnit Caesium reagiert es deutlich rascher. Aus den gelbbraunen Losungen (S"B= -15.2, h,,z= 100 Hz) erhillt man rnit Iod 3 quantitativ zuriick.Die Bildung von 3 aus 2 ist die erste NMR-spektroskopisch verfolgte 2~/3~-Valenzisomerisierung eines Organoborans rnit KZB=3 in ein Carbaboran rnit KZBT4 (vgl. Abb. 1). Offensichtlich hangt die Tendenz zur Carbaboran-Bildung auch bei unterschiedlichen Alkylresten an den Bor-Atomen des C4B6-Geriists von dessen C-Substituenten ab. Somit liegen jetzt erstmals experimentelle Belege1'51 fur die Konkurrenz klassischer und nicht-klassischer Strukturen in kohlenstoffreichen Carbaboranen des Typs

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Photolytic cleavage and isomerization reactions of (1-.sigma.,4-6-.eta.3-organo)tricarbonyliron complexes involving an (.eta.4-diene)(.eta.2-olefin)Fe(CO)2 intermediate. Quantum yields and mechanistic studies

Cited by 15 publications

References 0 publications

Iron Carbonyl-Promoted Isomerization of Olefin Esters to Their α,β-Unsaturated Esters: Methyl Oleate and Other Examples

Iron Carbonyl-Promoted Isomerization of Olefin Esters to Their α,β-Unsaturated Esters: Methyl Oleate and Other Examples

Of Iron, Ruthenium and Osmium

Carbonyleisen‐assistierte Verknüpfung von Cyclopolyenen mit Acrylsäuremethylester

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