Oxa-7-thia-twistanes

Base-hydrolysis of the 10 -acetoxy-twistane 249 (3.2.3.) yielded the alcohol 364, which on the one hand was converted to the tosylate 270 (starting material for reactions discussed in 3.2.3.) and on the other hand oxidized (Cr03/pyridine) to the 

7-thia-twistane (289 3.2.3.). Oxidation of the acetate 249 with one equivalent of hydrogen peroxide gave the S(7) -sulfoxide ) 23J (3.2.3.). 

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Oxa-7-thia-isotwistane [148), 10 -Hydroxy-2-oxa-7-thia-isotwistane 335) and 10 -Acetoxy-2-oxa-7-thia-twistane 249)... 

Treatment of unsubstituted 2-oxa-7-thia-isotwistane 148 2.2.3.1.) with raney-nipkel, yielded 74% of 9-oxabicyclo[4.2.1]nonane 408) and reductive desulfuration of the alcohol 335 (4.3.2.) 85% of endo-2-hydroxy-9-oxabicyclo[4.2.1 ]nonane (409) Analogous reaction of the 10 -acetoxy-twistane 249 (3.2.3.) with raney-nickelj however, led to endo-2-acetoxy-9-oxabicyclo[3.3.1]nonane (47( ) ... 

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