An approach to 2-azabicyclo[n.2.0]alkane derivatives (n = 1, 2), which relies on a
tandem Strecker reaction–intramolecular nucleophilic cyclization (STRINC) sequence
of the corresponding 2-(ω-chloroalkyl)cyclobutanones (in turn prepared by [2+2] cycloaddition
of keteniminium salts and ethylene) is described. The utility of the method is demonstrated
by multigram syntheses of bicyclic proline analogues, monoprotected diamines, as well
as parent 2-azabicyclo[4.2.0]octane.
Key words
cycloaddition - bicyclic compounds - amino acids - conformational restriction - cyclobutanes
- nitrogen heterocycles - keteniminium salts - Strecker reaction