Ciclização intramolecular do 1-benzil-2-alquinilbenzeno promovida por FeCl3 e dicalcogeneto de diorganoíla: síntese dos 9-(organocalcogênio)-5H-benzo[7]anulenos

Abstract

In the present work, a series of 1-benzyl-2-alkylbenzenes functionalized was subjected to intramolecular cyclization reaction promoted by iron(III) chloride with diorganyl dichalcogenide allowed the synthesis of 9-(organochalcogen)-5H-benzo[7]annulenes whereas the mutual action between diorganyl dichalcogenide and iron(III) chloride in a 0.5:1.0 mole ratio was essential in order to achieve the maximal yields of the products. The cyclization reaction tolerated a variety of functional groups, such as trifluoromethyl, chloro, fluorine and methoxyl, in both 1-benzyl-2-alkynylbenzenes and diorganyl diselenides, giving the seven-membered carbocyclic exclusively via a 7-endo-dig cyclization process, it resulted in a total of 23 samples in 45-77 % yield.