Stevens rearrangement migration group

STEVENS REARRANGEMENT. Migration of an alkyl group from a quaternary ammonium salt to an adjacent carbanionic center on treatment with strong base. The product is a rearranged tertiary amine, sulfonium, or sulfide. 

The last reaction shows that the benzyl group has a superior migration aptitude in the Stevens rearrangement. It is more reactive in nucleophilic... 

Incidentally, the oxidation step presumably involves a standard syn shift to an electron-deficient oxygen with retention at carbon. The [1,2] Stevens rearrangement also goes with retention of the migrating group (Zimmerman, 1963). 

In the case of elimination from (9), isoindole formation competes with 1,2-migration of the benzyl group (Stevens rearrangement ), which gives 1 -benzyl-2-methylisoindoline (10), and also with migration... 

With nBuLi and (2l6 R=Me, R1=H,R2=Ar) attack occurs at S to yield an ammonium ylide which collapses to an unusual Stevens rearrangement product (217) where an o-alkylthiophenyl group migrates... 

The Stevens rearrangement of a sulphonium salt involves treatment of the salt with base and leads to migration of a group from sulphur to an adjacent carbon atom (equation 91). Analogous Stevens rearrangement of ammonium salts and the related Wittig rearrangement of ethers are well known. 

Reaction of the tetrahydrobenzylisoquinoline 5 in the presence of potassium amide and metallic potassium led to the benzazonine 6. On the other hand, when the nucleophilic base dimsyl sodium was employed to effect the cycliza-tion of 5, the products were the indole 7 and the dibenzopyrrocoline tertiary base 8. The migration of the A -methyl group occurs possibly by a Stevens rearrangement. Base 7 was also produced by a similar cyclization of the 3,4-dihydrobenzylisoquinoline 9 (see Scheme 8.1). ... 

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