Thiols added easily to acetylenic compounds in the presence of Et3B to give alkenyl sulfides in good yields. The reaction of acetylenes with 3-methyl-2-buten-1-thio1 gave dihydro-thiophene derivatives in one pot.
We report the first copper-catalyzed olefinic ethoxy carbonyl difluoromethylation of alkenyl thioethers via direct C–H bond functionalization using BrCF2COOEt. The developed methodology allows the preparation of trisubstituted olefins with a controlled stereochemistry. A mechanistic study is reported and a radical mechanism is revealed.