Spiropentanes undergo carbonylation under an atmosphere of carbon monoxide in the presence of a rhodium(I)−phosphine catalyst, giving 3-methylcyclopent-2-enones. The catalytic cycle involves two mechanistically different carbon−carbon cleavage processes. The spiropentane carbonylation was successfully applied to a short synthesis of (±)-β-cuparenone.
Intramolecular palladium catalysed [3+2] cycloadditions of methylenecyclopropanes with acetylenic acceptors
作者:Hervé Corlay、Richard T. Lewis、William B. Motherwell、Michael Shipman
DOI:10.1016/0040-4020(95)00052-a
日期:1995.3
The synthesis and intramolecularpalladiumcatalysedcycloaddition reactions of eight methylenecyclopropanes containing alkyne acceptors are described. Bicyclo[3.3.0]octane and bicyclo[4.3.0]nonane rings systems can be successfully accessed using this chemistry. The nature of the substituents attached to the alkyne acceptor play a key role in the efficiency of the cycloaddition.
Total Synthesis of (±)-Cycloclavine and (±)-5-<i>epi</i>-Cycloclavine
作者:Filip R. Petronijevic、Peter Wipf
DOI:10.1021/ja2026882
日期:2011.5.25
indole alkaloid cycloclavine and its unnatural C(5)-epimer are described. Key features include the rapid construction of the heterocyclic core segments by two Diels-Alderreactions. An indole annulation was accomplished by a late-stage intramolecular Diels-Alder furan cycloaddition, and a methylenecyclopropane dienophile was used for a stereoselective intramolecular [4 + 2] cycloaddition to give the c