Thia-Payne rearrangement

Tetrahydroisoquinolines, synthesis of, 6, 3 Tetrahydrothiophenes, synthesis of, 6, 9 Thia-Payne rearrangement, 60, 1... 

Thia-Payne rearrangement (only forward direction) ... 

Scheme 10.6 Thia-Payne rearrangement nf representative 2..3-epoxy sulfides.

As with other rearrangements, the Payne rearrangement also has its variants. Similar transformations of substrates with nitrogen- or sulfur-based functionalities at the carbon atom adjacent to the epoxide are known as aza- or thia-Payne rearrangements, respectively, and there exist a nurnber of noteworthy previously reported examples of each. Although study of these systems has been somewhat limited in recent years, they are briefly surveyed in the following sections. 

Other thia-Payne-type rearrangements involve activation of 2,3-epoxypropyl thioethers with trimethylaluminum as the Lewis acid f Scheme IQ.ScL This activates the oxirane C—O bonds and leads to ready acceptance of intramolecular nucleophilic attack at the 2-position by the proximate sulfur atom Transposition of a methyl group from Me3Al to the episulfonium intermediate Int-3 furnished the product 23 with net retention of stereochemistry at C-2 due to double inversion at this site. 

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