Controlled Insertion Reaction of Thiirane into Carbamothioate: Novel Synthesis of Well-Defined Polysulfide

The insertion reaction of propylene sulfide (PS) into p -tolylcarbamothioate (PTCT) was examined in the presence of tetrabutylammonium chloride (TBAC) in 1-methyl-2-pyrrolidinone at 60 °C in the feed ratio of PTCT/PS = 1/1−1/40, affording the corresponding polysulfides in satisfactory yields. It was found that the molecular weights ( M n ′s) coincided with the feed ratios PS and molecular dispersity ratios ( M w / M n ) were very narrow ( M w / M n <1.10). i.e., this insertion reaction could be performed under the living system. Furthermore, the insertion living reaction of PS using tricarbamothioate was examined to give the controlled three-arms star-shaped polysulfides.