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Reactions of Diazo Compounds with Alkenes Catalysed by [RuCl(cod)(Cp)]: Effect of the Substituents in the Formation of Cyclopropanation or Metathesis Products
Author(s) -
Basato Marino,
Tubaro Cristina,
Biffis Andrea,
Bonato Marco,
Buscemi Gabriella,
Lighezzolo Filippo,
Lunardi Pamela,
Vianini Chiara,
Benetollo Franco,
Del Zotto Alessandro
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200801211
Subject(s) - cyclopropanation , diazo , metathesis , chemistry , organic chemistry , medicinal chemistry , catalysis , polymerization , polymer
The reaction of diazo compounds with alkenes catalysed by complex [RuCl(cod)(Cp)] (cod=1,5‐cyclooctadiene, Cp=cyclopentadienyl) has been studied. The catalytic cycle involves in the first step the decomposition of the diazo derivative to afford the reactive [RuCl(Cp){C(R 1 )R 2 }] intermediate and a mechanism is proposed for this step based on a kinetic study of the simple coupling reaction of ethyl diazoacetate. The evolution of the Ru–carbene intermediate in the presence of alkenes depends on the nature of the substituents at both the diazo N 2 C(R 1 )R 2 (R 1 , R 2 =Ph, H; Ph, CO 2 Me; Ph, Ph; C(R 1 )R 2 =fluorene) and the olefin substrates R 3 (H)CC(H)R 4 (R 3 , R 4 =CO 2 Et, CO 2 Et; Ph, Ph; Ph, Me; Ph, H; Me, Br; Me, CN; Ph, CN; H, CN; CN, CN). A remarkable reactivity of the complex was recorded, especially towards unstable aryldiazo compounds and electron‐poor olefins. The results obtained indicate that either cyclopropanation or metathesis products can be formed: the first products are favoured by the presence of a cyano substituent at the double bond and the second ones by a phenyl.