Reaktionen der Methylencyclopropane, VI 1) Palladium(0)‐katalysierte [2σ + 2π]‐Cycloadditionen des 1‐Methylen‐2‐vinylcyclopropans
1981; Wiley; Volume: 114; Issue: 10 Linguagem: Inglês
10.1002/cber.19811141013
ISSN0009-2940
Autores Tópico(s)Synthetic Organic Chemistry Methods
Resumo1-Methylen-2-vinylcyclopropan (1) wird an Palladium (0)/Triisopropylphosphan-Katalysatoren zu den Carbocyclen 3–5 cyclodimerisiert, die z. T. als Z/E-Isomere auftreten. Mit Norbornen erfolgt Codimerisierung zu den Tricyclen Z/E-6 und 7. In Konkurrenz zu diesen katalytischen Reaktionen lagert sich 1 rein thermisch in 3-Methylen-1-cyclopenten (2) um. Das zu Vergleichszwecken synthetisierte Allylidencyclopropan (9) geht an den verwendeten Palladium (0)-Katalysatoren weder Cyclo- noch Codimerisierung ein. Reactions of Methylenecyclopropanes, VI1) Palladium (0)-catalysed [2σ + 2 π] Cycloadditions of 1-Methylene-2-vinylcyclopropane 1-Methylene-2-vinylcyclopropane (1) is cyclodimerised at palladium (0)/triisopropylphosphane catalysts to give th carbocycles 3–5, which in certain cases are obtained as Z/E-6 and 7. The thermal rearrangment of 1 to 3-Cyclopentene (2) competes with these catalytic reactions. Allylidenecyclopropane (9), which was synthesized for reasons of comparison, does not undergo cyclo- ro codimerisation at the palladium (0) catalysts used here.
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