2.6- Dichloro-9-thiabicyclo nonane

Treatment of 1,5-cyclopentadiene with sulfur monochloride and then with sulfuryl chloride provided high yields of 2,6-dichloro-9-thiabicyclo[3.3.1]nonane 66 containing a six-membered tetrahydrothiopyran ring (2006MI212). The formation of thiopyran 66 is assumed by the authors to be the result of the reversible elimination-addition of SCI2, which is in equilibrium with sulfur monochloride, and of the high thermodynamic stability of 66 relative to the other monomeric and oligomeric sulfur dichloride addition products (Scheme 34). 

Thiiranes can be formed directly and stereospecifically from 1,2-disubstituted alkenes by addition of trimethylsilylsulfenyl bromide, formed at -78 C from reaction of bromine with bis(trimethylsilyl) sulfide (Scheme 7).12 A two-step synthesis of thiiranes can be achieved by addition of succinimide-A/-sulfe-nyl chloride or phthalimide-A -sulfenyl chloride to alkenes followed by lithium aluminum hydride cleavage of the adducts (Scheme 8).13 Thiaheterocycles can also be formed by intramolecular electrophilic addition of sulfenyl chlorides to alkenes, e.g. as seen in Schemes 914 and 10.13 Related examples involving sulfur dichloride are shown in Schemes 1116 and 12.17 In the former case addition of sulfur dichloride to 1,5-cyclooctadiene affords a bicyclic dichloro sulfide via regio- and stereo-specific intramolecular addition of an intermediate sulfenyl chloride. Removal of chlorine by lithium aluminum hydride reduction affords 9-thiabicyclo[3.3.1]nonane, which can be further transformed into bicyclo[3.3.0]oct-1,5-ene.16... 

Successive treatment with either SC12 or S2CI2 and SOCl2 converts 1,5-cyclooctadiene into 2,6-dichloro-9-thiabicyclo-[3.3.1]nonane 466. Both halogen atoms can be replaced by a wide variety of nucleophiles <2001JOC4386>. Following hydrolysis to the 2,6-diol, Swern oxidation affords the 2,6-dione (Scheme 160) < 19980SC692>. 

A. (1a,2tt,Sa,6a)-2,6-Dichloro-9-thiabicyclo[3.3.1]nonane (1). (Caution Preparation A should be carried out in a well-ventilated hood). A dry, 2-L, four-necked, round-bottomed flask is equipped with a sealed mechanical stirrer (Note 1), 1-L pressure-equalizing tunnel fitted with a drying tube, low temperature thermometer, and a nitrogen inlet. The flask is charged with 125 mL (1.02 mol) of 1,5-cyclooctadiene (Note 2) and 1 L of reagent dichloromethane, cooled to -50 to -60 C using an external acetone-dry ice bath, and the solution placed under a slow stream of dry nitrogen. To... 

The addition of sulfur dichloride and 1,5-cyciooctadiene to produce (1a,2a,5a,6a)-2,6-dichloro-9-thiabicyclo[3.3.1]nonane (1) has been described by several workers. - Determination of the stereochemistry of the product has been carried out using H NMR methods, and by means of the X-ray crystal structure of the corresponding sulfone derivative. The procedure described here as step A is that due to Corey and Block.3... 

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