Synthesis of cyclic trithiocarbonates from cyclic ethers and carbon disulfide catalyzed by titanium complex

Convenient synthesis of 1,3-dithiolane-2-thiones: cyclic trithiocarbonates as conformational locks

“…We isolated thiirane 2l as a major product in reaction of epoxide 1l (entry 12 in Table 2). The epoxides 1i and 1r (entries 9 and 18 in Table 2) produced mostly the corresponding thiiranes after 15-16 h, but finally gave trithiocarbonates when the time was extended to 72 h. Other researchers also reported isolation of thiiranes in certain conditions, 2,6,34 and the reaction of some thiiranes with carbon disulfide and base towards trithiocarbonates was described previously. 21,34,35 Noticeably, the configuration of the threemembered cycle in 8 is opposite to the configuration of the starting epoxide 1.…”

“…1 The procedures described previously for such a transformation used carbon disulfide in presence of a base and/or catalyst, and included an in situ formation of a xanthogenate or a similar intermediate, and then its reaction with an epoxide 2,[5][6][7][8][10][11][12][13][14] (for a detailed critical consideration of the literature data see ref.…”

“…We did not isolate these compounds, but the formation of some 1,3-oxathiolane-2-thiones in certain conditions was observed previously. 2,5,6,14 It is also known that these compounds react with excess carbon disulfide to give trithiocarbonates. 2,6 Apparently, in our case the subsequent addition of a nucleophile (Nuc = EtOCS 2 -, EtO -, or MeO -from the solvent) to probable intermediates 7 occurred quickly and caused cleavage of the heterocycle.…”

“…2,3 They are used as building blocks in the synthesis of new antibiotics, and as versatile ligands and polymers. [2][3][4][5][6] Trithiocarbonates are also of commercial importance in a wide variety of applications, for example as rubber stabilizers, ore flotation agents, and additives for lubricants and fuels. [7][8][9] Besides, they exhibit a remarkably high liver disorder suppressing effect, and hypocholesteremic, hypotriglyceridemic, radioprotective, and insecticidal activity.…”

“…[9][10][11][12] One of the most efficient methods for the synthesis of cyclic trithiocarbonates reported in literature is based on the reaction of epoxides with carbon disulfide (CS 2 ) in presence of a base and/or a catalyst. 2,[5][6][7][8][10][11][12][13][14] However, these procedures often suffer from low yields and poor selectivity. Depending on the catalyst and reaction conditions, a variety of products can be Our modified procedure has the same stereochemical outcome.…”