Alkenes iminium ion cyclization

On the basis of this rearrangement, an efficient synthetic route to pyrrolidines such as (46) was developed by Overman, starting from oxazolidine (42), via hydroxylated homoallylic imines such as (43 Scheme 22).Mechanistically, the formation of (46) may explained as a tandem-type combination of a cationic aza-Cope rearrangement with a subsequent Maimich cyclization (route a) or, alternatively, as an alkene-iminium ion cyclization/pinacolic rearrangement sequence (route b). 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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