Mechanism of the Rhodium Porphyrin-Catalyzed Cyclopropanation of Alkenes
- 12 June 1992
- journal article
- other
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 256 (5063), 1544-1547
- https://doi.org/10.1126/science.256.5063.1544
Abstract
The rhodium porphyrin-catalyzed cyclopropanation of alkenes by ethyl diazoacetate (EDA) is representative of a number of metal-mediated cyclopropanation reactions used widely in organic synthesis. The active intermediate in these reactions is thought to be a metal carbene complex, but evidence for the involvement of metal-olefin π complexes has also been presented. Low-temperature infrared and nuclear magnetic resonance spectroscopies have been used to characterize a rhodium porphyrin-diazoalkyl adduct that results from the stoichiometric condensation of the catalyst and EDA. Optical spectroscopy suggests that this complex is the dominant steady-state species in the catalytic reaction. This compound decomposes thermally to provide cyclopropanes in the presence of styrene, suggesting that the carbene is indeed the active intermediate. Metal-alkene π complexes have also been detected spectroscopically. Kinetic studies suggest that they mediate the rate of carbene formation from the diazoalkyl complex but are not attacked directly by EDA.Keywords
This publication has 21 references indexed in Scilit:
- Shape-selective and asymmetric cyclopropanation of alkenes catalyzed by rhodium porphyrinsOrganometallics, 1992
- Low-valent titanium porphyrin complexes. Synthesis and structural characterization of the first titanium(II) porphyrin complex, (.eta.2-diphenylacetylene)titanium octaethylporphyrinOrganometallics, 1991
- Synthesis of novel polyfunctional nickel(II)-nickel(II) dimer Ni2Cl2[C(SiMe3)(PMe3)]2 by photolysis of the first [(trimethylsilyl)diazomethyl]nickel(II) complex Ni[C(N2)SiMe3]Cl(PMe3)2Journal of the American Chemical Society, 1990
- Chiral Copper‐Semicorrin Complexes as Enantioselective Catalysts for the Cyclopropanation of Olefins by Diazo CompoundsAngewandte Chemie International Edition in English, 1986
- Reactivity of zero-valent metalloporphyrin dianions toward organic electrophilesJournal of the American Chemical Society, 1985
- Oxycyclopropanes in organochemical synthesisAccounts of Chemical Research, 1980
- Furan SynthesisHETEROCYCLES, 1980
- Enantioselective carbenoid cyclopropanation catalyzed by chiral vic-dioximatocobalt(II) complexes prepared from natural camphor and .beta.-pinene. Mechanism and stereochemistryJournal of the American Chemical Society, 1978
- Some Aspects on the Mechanism of Palladium-complex-catalyzed Decomposition of and Cyclopropanation with Ethyl DiazoacetateBulletin of the Chemical Society of Japan, 1978
- CarbalkoxycarbenesChemical Reviews, 1974