Photochemical intramolecular aromatic substitutions of the imidazol-2-yl radical are superior to those mediated by Bu<sub>3</sub>SnH
作者:Mairéad A. Clyne、Fawaz Aldabbagh
DOI:10.1039/b512729g
日期:——
Six-membered photochemical cyclisations of 2-iodo-N-(2-arylethyl)imidazoles proceeded regioselectively in higher yields than the equivalent tin hydride-mediated reactions. The decrease in yield of cyclisation products, 5,6-dihydroimidazo[2,1-a]isoquinolines containing strongly deactivating substituents on the aryl ring confirmed the electrophilic nature of the sigma-imidazol-2-yl radicals. The seven-membered
与碘化氢化锡介导的反应相比,2-碘-N-(2-芳基乙基)咪唑的六元光化学环化在区域选择性上以更高的产率进行。芳基环上含有高度失活的取代基的5,6-二氢咪唑并[2,1-a]异喹啉环化产物的收率降低,证实了sigma-咪唑-2-基的亲电性质。七元环化仅在光化学条件下才能成功,因为氢化锡会发生自由基还原。5,6-二氢咪唑并[2,1-a]异喹啉在硝酸和硫酸的2和8位发生硝化。