Pericyclic reactions in nature: Evidence for a spontaneous [1.7]-hydrogen shift and an 8πe electrocyclic ring closure in the biosynthesis of olefinic hydrocarbons from marine brown algae (phaeophyceae).
作者:Georg Pohnert、Wilhelm Boland
DOI:10.1016/s0040-4020(01)81756-7
日期:1994.8
The stereochemistry of the algal C11H16 hydrocarbon giffordene 3 results from a spontaneous [1.7]-sigmatropic hydrogen shift of the thermolabile (1,3Z,5Z,8Z)-undecatetraene 8. An 8πe electrocyclisation of (1,3Z,5Z,-7E)-nonatetraene 9 is substantiated for the biosynthesis of 7-methylcyclooctatriene 5, a product of the Mediterranean brown alga Cutleria multifida. Low temperature syntheses (−30 °C) of
藻类C 11 H 16烃giffordene 3的立体化学是由不耐热的(1,3 Z,5 Z,8 Z)-不十六碳烯8的自发[1.7]-σ氢转移引起的。的8πeelectrocyclisation(1,3- Ž,5 Ž,-7 ë)-nonatetraene 9被证实为7- methylcyclooctatriene的生物合成5,地中海褐藻的产物Cutleria凤尾。耐高温前体8和9的低温合成(−30°C)被描述。[1.7]-σ氢位移8 → 3(E a = 67.4 kJ mol -1)和8πe电环化9 → 5(E a = 59.4 kJ mol -1)的活化能是目前已知的最低值自然的周环反应。