| Affiliation: | 1. Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, F-35000 Rennes, France Laboratoire de Synthèse Organique Appliquée, Faculté des Sciences Exactes et Appliquées, Université Oran 1 Ahmed Ben Bella, BP 1524 El M'Naouer, 31000 Oran, Algeria;2. Laboratoire de Synthèse Organique Appliquée, Faculté des Sciences Exactes et Appliquées, Université Oran 1 Ahmed Ben Bella, BP 1524 El M'Naouer, 31000 Oran, Algeria;3. Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, F-35000 Rennes, France |
| Abstract: | When 2-iodobenzofuran was treated sequentially with lithium 2,2,6,6-tetramethylpiperidide in tetrahydrofuran at −50 °C and an aldehyde, the 2-substituted 3-iodobenzofuran resulting from the halogen dance was the only isolated product. However, from 2-iodobenzothiophene, these conditions led to mixtures in which the 2-substituted 3-iodobenzothiophene was always accompanied by the 2-substituted benzothiophene. The use of 2-bromobenzothiophene as a catalyst made it possible to significantly reduce this competitive dehalogenation. To confirm the halogen dance reaction, the products were unambiguously synthesized by using direct halogenations and deprotolithiation-trapping sequences as key steps. Our efforts to access 2,7-disubstituted and 7-substituted derivatives of benzofuran and benzothiophene have also been reported. |
