Addition of lithiated methoxyallene 2 to imines provided the expected allenyl amines in good yield. These could be cyclized with base or with silver nitrate to a variety of 2,5-dihydropyrrole derivatives. Selected examples describe their conversion to pyrrolidin-3-ones or 3-methoxypyrroles. Most importantly, this [3 + 2]cyclization method could also be applied to the synthesis of 2,5-disubstituted derivatives such as 26-28 and also to the preparation of the enantiopure compound 23.
The addition of lithiatedalkoxyallenes to N‐tosylimines followed by base‐, silver‐, or gold‐promoted cyclization of the addition products efficiently provides 2,5‐dihydropyrroles, which are excellent substrates for further transformations. Acids promote the hydrolysis of the enol ether moiety to deliver pyrrolidin‐3‐ones, and bases promote the aromatization to the elusive 3‐alkoxypyrroles.