Deoxygenation of Dithiirane 1-Oxides with Lawesson's Reagent Leading to the Corresponding Dithiiranes

Abstract

3,3-Disubstituted dithiirane 1-oxides were efficiently reduced with Lawesson's reagent (LR) to give the corresponding dithiiranes. X-ray diffraction analysis of 3,3-di(1-adamantyl)dithiirane is reported. Reaction of (34)S-labeled 3,3-di(1-adamantyl)dithiirane 1-oxide with LR produced the corresponding dithiirane in which the (34)S atoms were retained quantitatively.

Novel conversion of 6H‐1,3,5‐oxathiazine S‐oxides into 3H‐1,2,4‐dithiazoles by treating with Lawesson's reagent

“…Unequivocal mechanism for the reaction of sulfoxides 2 with a phosphorus sulfur reagent has not yet been established. Based on the analogous mechanism proposed during several decades for the thiation of sulfoxide with phosphorus sulfur reagents [1,2,[26][27][28][29][30][31][32] and by taking the present findings into account, the most likely formation pathway of 3 involving the formation of E and F through the reaction of 2 with LR is proposed. It was assumed that E might undergo stepwise mass fragmentation involving cycloreversion to give F along with the formation of pivalaldehyde and the further removal of PSOAnis from F to give the likely thiosulfine intermediates D, which causes facile ring closure to afford 3 as shown in Scheme 2.…”

“…It is commonly recognized that sulfoxides react with phosphorus sulfide reagents to afford the corresponding sulfides via the intermediary thiosulfoxides [1,2,[26][27][28][29][30][31][32]. But, in our cases, we could find a new preparation of 3H-1,2,4-dithiazoles 3 through the reaction of 2 with LR.…”

“…Compounds 2 having a sulfoxide moiety are generally expected to undergo oxygen-sulfur exchanging through the treatment with thiating agents via the four-membered phosphorus-and sulfur-containing intermediates [1,2,[26][27][28][29][30][31][32]. Unequivocal mechanism for the reaction of sulfoxides 2 with a phosphorus sulfur reagent has not yet been established.…”

Mechanism of the Reaction of Lawesson’s Reagent with N‐Alkylhydroxamic Acids

“…Although undetected as yet, it has been suggested that compounds of this type are LR transformation products formed in the deoxygenation of Soxides. [19] The 31 P NMR spectra obtained for unsubstituted hydroxamic acid 1a, which by reacting with LR produces a mixture of thionation and deoxygenation products, and for the hydroxamic acid undergoing reduction only (1d, Y = 4-NMe 2 ) are identical. This may prove that both processes, that is, thionation and deoxygenation, occur by the same mechanism and produce the same intermediates.…”

Synthesis and Reaction of α‐Dithiolactone

“…Three‐membered cyclic compounds containing two heteroatoms have been studied extensively 1–5. The isolation of a series of stable dithiiranes was reported by Ishii and Nakayama 1a–c. Methods for the synthesis of α‐lactams include the reaction of N ‐ tert‐ butyl‐2‐bromo‐2‐phenylacetamide with potassium tert ‐butoxide,2a the reaction of 2‐bromo‐3,3‐dimethyl‐ N ‐ tert‐ butylbutyramide with potassium tert ‐butoxide,2b and the reaction of α‐chloro‐α‐phenylacetanilide with sodium hydride 2c.…”