An Approach to the Stereoselective Synthesis of Enantiopure Dihydropyrroles and Aziridines from a Common Sulfinyl-Sulfinamide Intermediate

The diastereoselective addition of lithiated vinyl sulfoxides
to
enantiopure sulfinimines provides direct access to a wide assortment
of allylic sulfinamides in good yields and excellent selectivities.
These adducts are key precursors to differently functionalized cis- and trans-dihydropyrroles. Modulation
of the protecting group on nitrogen prior to cyclization has a significant
impact on the stereochemical outcome, allowing for the selective preparation
of 2,5-cis- or 2,5-trans-3-sulfinyl
disubstituted dihydropyrroles from a common sulfinamide intermediate.
Further research on halocyclization conditions has also yielded a
stereoselective synthesis of trisubstituted vinyl aziridines from
these chiral sulfinamides, simply by changing the halogenating agent.