13-Oxathiolane 3-oxides

The transformation of the saturated compounds into 1,2-oxathiolanes may be achieved under basic conditions. For example, cis- and frans-2,4-diphenylthietane 1,1-dioxides react with magnesium f-butoxide in refluxing ether to give a stereospecific ring expansion into cis- and trans-3,5-diphenyl- 1,2-oxathiolane 2-oxide, respectively. The reaction for the cis compound is shown in equation (42) the mechanism is unknown (B-73MI43000). 

Apart from photolysis of 1,2-dioxolanes, most studies in this section involve A-oxidized 1,2-oxathiolane derivatives, although the remarkable reactivity of the 1,2-oxathiolane 34 is notable. The reactivity of 1,2-oxathiolane 2-oxides is covered in a review on the properties of sultines <1996UK156>. 

The stable 1,2-oxathiolane 34 was formed by cycloaddition of the sulfine thiofluorenone j -oxide 133 to ( )-cyclooctene (Scheme 5) <1998JA4861>. Iron-substituted 1,2-oxathiolane 2-oxides 39 and 40 were formed in 94% yield by treating the corresponding cyclopropyliron compound 134 with SO2 in MeCN <19980M5534> while reaction of propargyliron compounds 135 with SO2 or SO3 gave the compounds 48 and 50, respectively (Scheme 5) <2000JOM(598)150>. 

New material on the saturated analogues, 1,2-oxathiolane 2-oxides (13) and 2,2-dioxides (14), as well as the l,2-oxathiolan-5-one 2-oxide (15) and 2,2-dioxide (16) and l,2-oxathiolan-4-one 2,2-dioxide (17) systems is also included. Finally there have been a few reports on sulfuranes of the... 

Table 1 Proton NMR data for some 1,2-dioxolane and 1,2-oxathiolane 2-oxide and 2,2-dioxide...

JA2393>. The nucleophilic attack on cystine-derived chiral 4-amino-1,2-oxathiolane 2-oxides (57) by alkyllithiums takes place at the sulfur atom with inversion of configuration to afford (58) (Equation (4)) <81JOC5408>. 

Amino substituted)-l,3-dioxolanes and -oxathiolanes are readily available as shown in equation (46), while derivatives of the corresponding 2-ylium species are also easily prepared (equation 47) (72CRV357). A 4-amino-1,2-oxathiolane 2-oxide was recently prepared in high yield by total synthesis (81JOC5408). 

Flash vacuum pyrolysis of 5-phenyl-1,2-oxathiolan 2-oxide (459) affords phenylcyclopropane with loss of sulphur dioxide,the l,2-oxathiolan-5-one... 

Ethylmagnesium bromide tert-hutanol 1,2-Oxathiolane 2-oxides from thietane dioxides Stereospecific ring expansion... 

Oxathiolane 2-oxides. Startg. m. treated withN-dilorosuccinimide in methylene chloride 3-methyl-l,2-oxathiolane 2-oxide. Y 72%. - SO2CI2 can be used instead of N-chlorosuccinimide. F. e. s. N. K. Sharma, F. Jung, and T. Durst, Tetrah. Let. 1973, 2863 ethylenesultines and their conversion to 1,3-dienes s. F. Jung et al.. Am. Soc. 96, 935 (1974). 

The reaction of sulfur dioxide with cyclopropanes in trifluoroacetic acid at 20 °C affords mixtures of isomeric 1,2-oxathiolane 2-oxides (y-sultines). From cis-1,2-diphenylcyclopropane a mixture of the (2,3-cw)-2-oxide 19 (yield, 52 %) and the (2,3-trans)-2-oxide 20 (yield, 18 %) is obtained... 

In the reaction of trani -diarylcyclopropanes and SO2 four diastereoisomers are obtained. From phenylcyclopropane, the diastereoisomers of 5-phenyl-1,2-oxathiolane 2-oxide are obtained in 66% yields. Similarly, diarylcyclopropanes react with sulfur dioxide to give the five-membered ring [3-1-2] cycloadducts From l-methyl-2-phenylcyclopropane a mixture of mainly three isomeric y-sultines are obtainedIn Table 7.3 some y-sultines 21, obtained in this manner, are listed. 

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