9-THIABICYCLO NONANE-2,6-DIONE

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>. 

The diketone (3) Is a versatile intermediate for the preparation of 9-thiabicyclo[3.3.1]nonane derivatives and provides a simple synthetic entry to a number of other heterocycles such as the 2-thiaadamantane. 3 4 thiacyclohexane, thiacycloheptane, 2,6-dlthiaadamantane, 6 and 2-thiabrexane 7 ring systems. Only one previous procedure for Its preparation has been published. This method involves the oxidation of diol (2) with chromium trioxide in pyridine and diohioromethane to yield 9-thiabicyclo[3.3.1]nonane-2,6-dione (3) in 65% yield. In practice this reaction Is difficult to carry out reproducibly because of precipitation of tarry chromium salts which make adequate stirring and extraction of the product very difficult. Consequently the dione (3) is often accompanied by partly oxidized material and/or material where the sulfur atom has been oxidized. The method reported here avoids these technical difficulties and affords a considerably Increased yield. 

C. 9-Thiabicyclo[3.3.1]nonane-2,6-dione(3). (CautionI Oxalyl chloride and dimethyl sulfoxide are reported to react explosively at room temperature. Preparation C should be carried out in a well-ventilated hood since a co-product of the reaction is dimethyl sulfide). To a 1-L, three-necked flask equipped with a magnetic stirring bar, low temperature thermometer, dropping funnel protected from moisture by a drying... 

Photolysis of 9-thiabicyclo[3.3.1]nonane-2,6-dione (45) gave monocyclic products, e.g. (46), by cr-cleavage and C —S bond cleavage. The 2,6-dithia-... 

CbH,o02S, 9-Thiabicyclo[3.3.1]nonane-2,6-dione, 45B, 372 C8Hio02S2f 5,6-Dihydro-6-acetoxy-1,4-dithiocin, 41B, 398 CsHioSe f 1-(2-(1,3-Dithiolanylidene))-2,3,6,9-tetrathiaspiro[4.43-nonane, 40B, 317... 

---