Tandem 2,3-rearrangement/heterocyclization

Pearce, A J, Mallet, J M, Sinay, P, One-step synthesis of disaccharide mimetics via tandem rearrangement of unsaturated disaccharides. Heterocycles, 52, 819-826, 2000. 

Tandem reactions of heterocycles combining Diels-Alder reactions with sig-matropic rearrangements 98S227. 

Tandem reactions combining Diels-Alder reactions with sigmatropic rearrangements in syntheses of heterocycles 98S227. 

Stereoselective synthesis of functionalized carbocyclic and heterocyclic compounds via tandem ester enolate Claisen rearrangement/RCM has been reported (Eq.79) [131,132],... 

Schinzer and Langkopf (83) reported in 1994 their synthesis of various seven- and eight-membered iV-heterocyclic systems resembling the benza-zepine framework of cephalotaxine (Scheme 49) by means of tandem Beckmann rearrangement-allylsilane cyclization. Treatment of compounds 286 and 287 with diisobutylaluminum hydride yielded the heterocycles 288 and 289, respectively. [See Note Added in Proof, p. 264.]... 

Tandem aza-Cope rearrangement of in situ generated iminium ions-cyclization processes are widely used for the synthesis of heterocycles. For example, dehydroyohimbane (5) is prepared by the reaction sequence shown via the Cope precursor 2962. 

Brook rearrangement in tandem bond formation strategies (formation of heterocycles as the result of C —> O or O — C migrations of silyl groups) 01T2065. 

Treatment of the oxime 6>-mesylate 13 with DIBAL resulted in the formation of the tricyclic benz-3-azepine 14 in a stereoselective tandem Beckmann rearrangement / allylsilane cyclisation <97SL632>. Treatment of ketoximes with divinylketone or its equivalents affords mixtures of the bridged heterocycles 15 and 16 <97TL6099>. In most cases formation of the 7-membered ring predominates, particularly in polar solvents. 

Overman and co-workers continue to report new applications of their tandem cationic aza-Cope rearrangement-Mannich cyclization route to nitrogen heterocyclic systems. Perhaps the nicest illus-... 

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