A Two-Step, Three-Component Queuing Cascade Leading to Dihydrobenzoxepine and Dihydrobenzazepine Derivatives
| Autor: | Armin de Meijere, Natasa Valentic, Mathias Noltemeyer, Baris Yucel |
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| Rok vydání: | 2007 |
| Předmět: |
Methylenespiropentane
Bicyclic molecule Dimethyl fumarate 010405 organic chemistry Aryl Organic Chemistry Iodobenzene chemistry.chemical_element 010402 general chemistry 01 natural sciences Medicinal chemistry Benzoxepine 0104 chemical sciences 3. Good health chemistry.chemical_compound Bicyclopropylidene Benzazepine chemistry Nucleophile Morpholine π-Allylpalladium species Organic chemistry Physical and Theoretical Chemistry Dendralene Palladium |
| Zdroj: | European Journal of Organic Chemistry |
| ISSN: | 1099-0690 1434-193X |
| Popis: | A palladium-catalyzed reaction of methylenespiropentane (11) with iodobenzene (12) under typical Heck conditions [Pd(OAc)2, PPh3, Et3N, DMF] produced a mixture of the unstable [3]dendralene 13 and allylidenecyclopropane 14 in 38 % yield. When an analogous reaction with iodobenzene was carried out in the presence of morpholine (25) and of tris(2-furyl)phosphane (TFP) instead of triphenylphosphane, the dienes 26, 28 and 31 were generated by nucleophilic trapping of π-allylpalladium intermediates 30 and 32. The cross coupling of methylenespiropentane (11) with the functionalized aryl iodides 33a–g in the presence of a palladium precatalyst [Pd(OAc)2, TFP, Et3N, DMF] at 80 °C, 3 h, provided the seven-membered 3,4-dimethylene-substituted heterocycles 34a–g and 35b which, upon addition of dimethyl fumarate (19), underwent Diels–Alder reactions to furnish bicyclic and higher oligocyclic dihydrobenzoxepine and-benzazepine derivatives 36a–g and 37b, yet in rather moderate yields of 18–29 % only. The overall process constitutes a one-pot, two-step, three-component queuing cascade.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) |
| Databáze: | OpenAIRE |
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