Expedient Synthesis of Fused Azepine Derivatives Using a Sequential Rhodium(II)-Catalyzed Cyclopropanation/1-Aza-Cope Rearrangement of Dienyltriazoles
作者:Erica E. Schultz、Vincent N. G. Lindsay、Richmond Sarpong
DOI:10.1002/anie.201405356
日期:2014.9.8
reported. The process involves an intramolecular cyclopropanation of an α‐imino rhodium(II) carbenoid, leading to a transient 1‐imino‐2‐vinylcyclopropane intermediate which rapidly undergoes a 1‐aza‐Coperearrangement to generate fused dihydroazepine derivatives in moderate to excellent yields. The reaction proceeds with similar efficiency on gram scale. The use of catalyst‐free conditions leads to the formation
报道了一种从带有系链二烯的 1-磺酰基-1,2,3-三唑形成稠合二氢氮杂卓衍生物的一般方法。该过程涉及 α-亚氨基铑 (II) 类卡宾的分子内环丙烷化,产生短暂的 1-亚氨基-2-乙烯基环丙烷中间体,该中间体迅速发生 1-氮杂-Cope 重排,以中等至优异的产率生成稠合二氢氮杂卓衍生物。该反应在克规模上以类似的效率进行。使用无催化剂条件导致形成新的 [4.4.0] 双环杂环。
The nickel-catalyzed intramolecularcycloaddition of dienes with unactivatable alkynes is found to proceed under mild conditions while the corresponding Diels-Alder cycloaddition of the same substrates either fails or occurs only under forcing conditions. The nickel-catalyzed cycloaddition is also shown to occur with retention of stereochemistry and is not significantly influenced by electronic effects
Rhodium(II)-catalyzedintramolecular [4 + 3] cycloadditions of dienyltriazoles have been developed, which enable the efficient synthesis of various fused 2,5-dihydroazepines. Mechanistically, the titled reaction proceeds via an interesting tandem cyclopropanation/aza-cope rearrangement.