Sultines, Sultones, and Related Systems

Sultines, Sultones, and Related Systems.— The /3-sultine (103) has been isolated as a relatively stable crystalline solid. It decomposes quantitatively to 2-methyl-1,1-diphenylpropene, with a half-life of 23 h in CHgCla solution at 30 °C. Partial resolution of the cyclic sultines (104) and (105) was accomplished by interrupting 

The reduction of a number of sultones in the bornyl and camphene series with lithium aluminium hydride can lead to a variety of products, depending on the reaction conditions. Thus 10-isobornyl sultone, when reduced in ether at room temperature, gives the corresponding sultine in 70% yield, whereas reduction in refluxing THF afforded l-mercaptomethyl-2-exo-hydroxy-7,7-dimethyl-bicyclo-[2,2,1 ]heptane. The propargylic sulphite (106), when heated to 180 °C, gave sultone (107) in 22% yield its structure was proved by A -ray studies. The 

The first cyclic sulphenate (109) has been reported. This compound was prepared in 85% yield by the reaction of the mercapto-alcohol (110) with Brj in CCI4 containing pyridine at - 5 °C. The reaction of (109) with water or moist air gave the corresponding sulphinate, while treatment with 2 equivalents of the potassium salt of hexafluoro-2-phenylpropan-2-ol afforded the sulphurane (111). 

Variable-temperature n.m.r. studies suggested that (111) is best assigned the structure shown, in which the five-membered ring occupies the diequatorial position. In contrast, the five-membered ring of the sulphurane (112), prepared at — 60 °C by the interaction of (MeO)aS with 3,3-dimethyl-l,2-dioxetan, was assigned an axial-equatorial conformation on the basis of the non-equivalence of the two methoxy-groups in the n.m.r. spectrum. Full details of the study of sulphuranes related to (113) have appeared.  

Schank, R. Wilmes, and G. Ferdinand, Internat. J. Sulfur Chem., 1973, 8, 397. 

Sultines, Sultones, and Related Systems.—A general synthesis of sultines (144) (cyclic sulphinate esters), based on the reaction of t-butyl hydroxyal-kyl sulphoxides (145) with SO2CI2 or N-chlorosuccinimide, has been developed. The method was shown to be suitable for the preparation of sultines varying in ring size from 5 to 8 and having a variety of alkyl or aryl substitution patterns. 

The transformation from (145) to (144) occurred via initial formation of the chloro-oxosulphonium salt (146), then cycUzation to the alkoxyoxosul-phonium salt (147), followed by cleavage of the carbon-sulphur bond to give 

The (T-bonded cyclopropyl-iron complex (151) reacted with SOj to give mainly the sultine (152) and a small amount of the metal allyl sulphone (153). Electrophilic attack on the C-1—C-2 bond of the cyclopropane by SO2 should give the intermediate (154), which can either cyclize to (151) or. 

A 7-sultine (155) was obtained from thionyl chloride and exo-tricyclo-[3,2,l,0 ]oct-6-en-anti-8-ol. The electrophilic exo-cis-addition to the double bond in a [2,2,1] system is somewhat unusual, but the structure of (155) 

During a study of the mechanism of the thermal rearrangement of 10-isobomyl sultone (158) to exo-camphene sultone (159), the endo-cam-phene sultone (160) was isolated after partial isomerization however, (160) is probably not a direct intermediate but a dead-end product which underwent re-ionization under the reaction conditions and eventual conversion into the thermodynamically more stable (159). Two possible mechanisms for the rearrangement (158) to (159) were considered. The first 

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