Molecular rearrangements Smiles rearrangement

A symmetrical tricyclic 1,3,6-thiadiazepine derivative 152 (Scheme 48) has been synthesized [68,69] in 54% yield starting from 5-bromo-thiadiazole derivative 144 and 1,2-diaminobenzene 145. The synthesis embraces two types of molecular rearrangements Smiles and Dimroth s. 

A Smiles rearrangement (equation 28) was also responsible for the secondary loss of SOz in the El induced fragmentation of 2-(p-chlorophenoxymethyl)-3-arylsulfonylmethyl-5-chlorobenzo(h)thiophenes (59) but not in their 3-alkylsulfonylmethyl derivatives33. In the latter, the loss of RS02 from the molecular ions and those of RS02 and RSOH from the [M — C1C6H40] + ions are the predominant routes of fragmentation. 

One advantage of the U-4CR lies in its ability to efficiently generate substances of significant molecular complexity from simple starting materials. As a result, the products of these reactions are often well suited for further transformations via tandem processes. Smiles rearrangements, ... 

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