Cope rearrangements in the benzo[b]thiophene series was written by Sura, Tushar P.;MacDowell, Denis W. H.. And the article was included in Journal of Organic Chemistry in 1993.Synthetic Route of C8H5IS This article mentions the following:
The inability to observe Cope rearrangement products at elevated temperatures for di-Et α-allyl-2-naphthalenemalonate and di-Et α-allyl-9-phenanthrenemalonate does not extend to analogous systems resulting from replacement of the aromatic units by 2- and 3-benzo[b]thiophene nuclei. Thermal rearrangement of di-Et α-allyl-3-benzo[b]thiophenemalonate at 215-255°C for 11 h gave the expected Cope rearrangement product di-Et 2-allyl-3-benzo[b]thiophenemalonate (8%) accompanied by trans- and cis-Et 2,3-dihydro-1-(ethoxycarbonyl)-1H-benzo[b]cyclopenta[d]thiopehen-2-acetate in 10% yield 5% yield, resp. The attempted structure verification of 2-allyl-3-benzo[b]thiophenemalonate by an independent route gave di-Et 2-(1-propenyl)-3-benzo[b]thiophenemalonate which when heated at 230-240°C for 18 h gave 1-carbethoxy-2-hydroxy-3-methyldibenzothiophene as a major product. Similar results were observed with 2-substituted analogs of di-Et α-allyl-3-benzo[b]thiophenemalonate, both di-Et 3-allyl-2-benzo[b]thiophenemalonate and Et 1,2-dihydro-3-(ethoxycarbonyl)-3H-benzo[b]cyclopenta[d]thiophene-2-acetate were formed. In the experiment, the researchers used many compounds, for example, 3-Iodobenzo[b]thiophene (cas: 36748-88-6Synthetic Route of C8H5IS).
3-Iodobenzo[b]thiophene (cas: 36748-88-6) belongs to iodide derivatives. Organoiodine compounds occur widely in organic chemistry, but are relatively rare in nature. The C–I bond is the weakest of the carbon–halogen bonds. These bond strengths correlate with the electronegativity of the halogen, decreasing in the order F > Cl > Br > I.Synthetic Route of C8H5IS
Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com