Direct Synthesis of 3-Methylselenophene and 3,4-Dimethylselenophene

Synthesis of Selenophenes

“…A more recent synthesis of 3,4 dimethylselenophene 49 is described by Paulmier [94]. The 2,3-dimethyl-1,3butadiene 48 is introduced by a nitrogen stream in a glass tube heated at 450°C and containing gaseous selenium and fragments of pyrex.…”

Silver-Mediated Intermolecular [2 + 2 + 1] Cyclization of Terminal Alkynones with Elemental Selenium: Regioselective Synthesis of 2,4- or 3,4-Dicarbonylselenophenes

“…They used 2,3-dimethyl-1,3-butadiene driven by nitrogen through a glass tube kept at 450 °C containing fragments of pyrex glass or sand and selenium vapor to achieve the reaction (Scheme 1b). 3 Nakayama and co-workers also found that the reaction of 3-butyn-2-one with elemental selenium at 205−215 °C in benzene in a stainless autoclave could afford 2,4-and 2,5diacetylselenophenes in 32 and 29% yields, respectively (Scheme 1c). 4 In addition, Chen's group reported a novel synthesis of 2,4-disubstituted selenophenes from elemental selenium and arylvinyl iodonium salt catalyzed by a Cu salt.…”

“…Subsequently, Barbey’s group developed an interesting reaction to prepare 3,4-dimethylselenophenes. They used 2,3-dimethyl-1,3-butadiene driven by nitrogen through a glass tube kept at 450 °C containing fragments of pyrex glass or sand and selenium vapor to achieve the reaction (Scheme b) . Nakayama and co-workers also found that the reaction of 3-butyn-2-one with elemental selenium at 205–215 °C in benzene in a stainless autoclave could afford 2,4- and 2,5-diacetylselenophenes in 32 and 29% yields, respectively (Scheme c) .…”