Ruthenium complex-catalyzed formation and cleavage of carbon-carbon sigma-bonds. On the requirement of highly qualified tuning of the reaction conditions
T. Mitsudo et T. Kondo, Ruthenium complex-catalyzed formation and cleavage of carbon-carbon sigma-bonds. On the requirement of highly qualified tuning of the reaction conditions, SYNLETT, (3), 2001, pp. 309-321
Characteristic aspects of ruthenium complex-catalyzed carbon-carbon bond fo
rming reactions and carbon-carbon sigma -bond cleavage reactions are discus
sed. It is pointed out that these ruthenium complex-catalyzed reactions req
uire highly qualified tuning of reaction conditions with substrates to atta
in high yields and selectivities of the products. In the [2+2] cycloadditio
n of alkynes and norbomenes catalyzed by RuH2(CO)(PPh3)(3), Ru(cod)(cot)/PB
u3 [cod:1,5-cyclooctadiene, cot:1,3,5-cyclooctatriene] and Cp*RuCl(cod) [Cp
*: pentamethylcyclopentadienyl] giving cyclobutenes, matching of the alkyne
derivative with the catalyst is essential. In the Ru,(CO),,-catalyzed intr
amolecular carbonylative cyclization of 1,6-enynes giving bicyclic cyclopen
tenones, remarkable solvent effects are observed. Linear codimerization of
diphenylacetylene and methyl acrylate is catalyzed by Ru(cod)(cot)/pyridine
; however, for the reaction of diphenylacetylene with N,N-di-methylacrylami
de, pyridine is not required. N,N-Dimethylacrylamide works as a ligand as w
ell as the substrate. Ru(cod)(cot)/dimethyl fumarate catalyzes novel dimeri
zation of 2,5-norbomadiene in THF to give pentacyclo[6.6.0,0(2.6).0(3.13) .
3(10.14)]tetradeca-4 1-diene (PCTD) via carbon-carbon bond cleavage. In DMS
O, the major product is heptacyclo[6.6.0.0(2.6).0(3.13) .0(4.11).0(5.9).0(1
0.14)]tetradecane (HCTD) in place of PCTD, and no cleavage of the carbon-ca
rbon bond occurs. The first catalytic deallylation of tert-homoallyl alcoho
ls is achieved. The presence of an excess of allyl acetate is essential. Th
e reaction can be applied to a ring-opening reaction of cyclic homoallyl al
cohols. The reasons for the requirement of highly qualified tuning of the r
eaction conditions for the ruthenium catalysts are discussed comparing with
the catalytic activities of palladium complexes.
Introduction
Reactions via Ruthenacycles
[2+2] Cycloaddition Reaction of Alkenes and Alkynes via Ruthenacyclopentene
s
Syntheses of Cyclopentenones via Ruthenacycles
Linear Codimerization of Alkynes with Monoenes or Dienes
Linear Codimerization of Internal Alkynes with Monoenes
Linear Codimerizaiton of Terminal Alkynes with Dienes
Organic Syntheses Involving Catalytic Cleavage of Carbon-Carbon sigma -Bond
s
Novel Dimerization of 2,5-Norbornadiene to PCTD
Deallylation of tert-Homoallyl Alcohols
General Discussion
Conclusion