A convenient synthesis of 1,3‐dithioles, 1,3‐thiaselenoles and 1,3‐thiatelluroles

Abstract

Abstract. Reaction of 1-(chloromethylthio)-I-alkynes (RC=C-S-CH,Cl, R = alkyl or phenyl) with an alkali metal sulfide, selenide or telluride gives 4-substituted 1,3-dithioles together with the corresponding 1,3-thiaselenoles and 1,3-thiatelluroles in good yields. The compounds RC-C-S--CH,CI can be obtained either from lithium alkynethiolates (RCEC-SLi) and BrCH,CI or from alkynyllithium (RC=C-Li) and chloromethyl thiocyanates (CICH,S-C=N).

A Traceless Tether Strategy for Achieving Formal Intermolecular Hexadehydro-Diels–Alder Reactions

“…Moreover, these ambident nucleophiles are known to cleanly alkylate at the soft sulfur atom. 5 Indeed, we found that the diynes 12 and 13 could be efficiently prepared by sequential in situ alkylation with either dibromo- or diiodomethane, followed by alkyne desilylation. These bisalkynes are known entities, having been previously prepared by an alternative sequence—namely, sulfenylation of trimethylsilylethynyllithium with CH 2 (SCN) 2 (11% after deprotection).…”

“…11 ). Moreover, these ambident nucleophiles are known to cleanly alkylate at the soft sulfur atom . Indeed, we found that the diynes 12 and 13 could be efficiently prepared by sequential in situ alkylation with either dibromo- or diiodomethane, followed by alkyne desilylation.…”