Adamantanethione 5-oxide

The [3+2] cycloadducts of sulflnes with aliphatic thiones are more stable. For example, reaction of the same sulfine with adamantanethione at 110 °C for 10 min affords a 86 % yield of the [3+2] cycloadduct. A bis-spiroadamane derivative is obtained in 85 % yield from adamantanethione and adamantanethione 5-oxide". ... 

The absence of a convenient method for the preparation of enethiolisab-le thioketones prompted us to fulfil this need. The development of aliphatic thioketones has so far been mostly restricted to examples with steric protection, such as thiocamphor and adamantanethione. Among the difficulties for a general synthesis of aliphatic and acyclic thioketones were easy enethiolisation (enethiols are stable tautomers with thermodynamic stabilities close to those of the thione form), oligomerisation, and susceptibility to air oxidation. They were solved by the adaptation of a former German reac-... 

High-level quantum-chemical calculations on the 3 + 2-cycloadditions of thioformaldehyde 5 -imides, S -methylide, S-oxide, and 5-sulfide have been reviewed. Theoretical studies on the 1,3-dipolar cycloaddition between thioketene 5-oxide and methyleneimine show that this reaction is concerted but non-synchronous. Adamantanethione 5-methylide reacts with thiocarbonyl compounds to produce 1,3-dithiolanes. A density-functional-theory study of the cycloaddition of the sulfine H2CSO predicts the 2 + 3-mechanism having the lowest pathway, with an activation barrier of 12.3kcalmoP. R The thermal and photochemical reactions of fluorenethione 5-oxide (69) with cyclooctyne (70) involves an initial 1,3-dipolar cycloaddition to produce the adduct (71), followed by an efficient sulfur transfer to cyclooctyne to produce the enone (72) and the dithiin (73) (Scheme 26). ° ... 

Hetero Diels-Alder reactions of 3,4-di-fcrf-butyIthiophene 1-oxide with thioaldehydes and thioketones take place exclusively at the syn-jt-face with respect to the S=0 bond, like the Diels-Alder reactions with ketones. Thiophosgene and adamantanethione can also react with 3,4-di-(erf-butylthiophene 1-oxide to afford the corresponding syn-tr-face products (Scheme 44) [49]. 

Alkene Synthesis.—The alkene synthesis by two-fold extrusion processes (see Vol. 3, pp. 246, 693) is discussed in Chapter 2 of this Volume (p. 89). The addition of diazo-compounds to suitable thiones provides an alternative route to A -l,3,4-thiadiazolines, which give episulphides on pyrolysis and hence alkenes on further reaction with triphenylphosphine. The symmetrical 1,3,4-thia-diazoline represents the normal direction of cycloaddition, but the orientation of addition of diazomethane to adamantanethione is governed by the nature of the solvent, and the unsymmetrical adduct predominates in solvents of higher polarity. A -l,3,4-Thiadiazoline-2,5-dione (148) is generated by oxidation of... 

To date, sulphines have been prepared by two methods, the dehydrohaloge-nation of sulphinyl chlorides or the oxidation of thiocarbonyl compounds, but neither has been successful for the preparation of aliphatic sulphines. Zwanenburg et al. now have reported that some non-enolizable thiones, such as adamantanethione and the cyclobutanedithione (107), could be... 

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