Abstract
Silica gel and activated clay, behaving as Lewis acids, reacted with N-acyl-2,2-dimethylaziridines 1 to lead to pentacoordinated aziridinium silicate ions. The regiospecific ring opening on the CMe2 carbon side of the intermediate I involves, after removal of the catalyst, the zwitterion II. The zwitterion II undergoes either a transfer of proton leading to the N-methallylamide 2 or intramolecular cyclization reaction leading to the oxazoline 3. The unstable oxazoline 3 on catalyst is hydrated in turn into amidoalcohol 4 via the oxazolinium silicate III.