1.2.3- Oxathiazolidines

Diaza-l,6-dioxa-6 -thiapentalene has been extensively studied by various diffraction methods X-ray, neutron and electron spectroscopy <1996CHEC-II(4)409>. There has been substantial progress in the spectral investigation of disubstituted 1,2,3-oxathiazolidine 2-oxides. Infrared (IR) and mass spectra were less employed for dithiazoles and oxathiazoles than other methods. 

A similar synthesis of enantiopure (l )-sulfinamides 123 from indane-derived toluenesulfonyl 1,2,3-oxathiazolidine-2-oxide 121 has been developed. This method includes chemoselective ring opening with inversion of configuration at the sulfur atom, using Grignard reagent at the first step and lithium amide in liquid ammonia in the second step (Scheme 17) <2002JA7880>. Intermediate stable and crystalline sulfinate esters 122 were isolated in >95% yield in diastereopure form. 

Reaction of A-sulfinyl derivative 162 with oxiranes in the presence of a catalyst such as Et4NBr and LiCl or LiBr gave the cyclocondensation products - 1,2,3-oxathiazolidines 163 (Equation 47) <1996JFC49>. 

The traditional synthesis of cyclic sulfimidates from /3-aminoalcohols and SOCl2 in the presence of amine as a base has been developed further to the preparation of the enantiopure monocyclic as well fused sulfimidates (Schemes 26 and 27). 1,2,3-Oxathiazolidine mono-.Y-oxides are readily oxidized to corresponding sulfamidates by RuCR and NalCb, and the synthesis of sulfamidates can be performed in a one-pot procedure from -aminoalcohols without isolation of intermediate sulfimidates (Equation 37). The reaction of sulfamate esters 145 with PhI(OAc)2 and various catalysts proved to be a reliable method for the enantioselective preparation of cyclic sulfamidates 146 (Equation 35). 

Scheme 33 Acid-catalyzed hydrolysis of 1,2,3-oxathiazolidine S-oxide...

L-Serine Osulfonate has been cyclized to the 1,2,3,-oxathiazolidine (187) using DCC in DMF (67BCJ1554). 

The use of aminosulfites in the synthesis of o.p. sulfoxides was described for the first time in 1973 by Wudl and Lee,98 using ephedrine as chiral auxiliary. In 1991, Benson and Snyder reported a modification of the Wudl and Lee procedure, obtaining o.p. sulfoxides in high yield by sequential displacement reactions of organometallic reagents on the 1,2,3-oxathiazolidine-S-oxide (aminosulfite 70), obtained from ephedrine and thionyl chloride.99... 

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