Attempted synthesis of 2-azetidinones via ester enolate condensation reactions with imines and thioimidates

摘要

Reaction of the imines 1 and ethyl isobutyrate in the presence of LDA yields #beta#-lactams 2, whereas thioimidate 4 with the same enolate gives the substituted products 5. When phosphorous containing heterocyclic compound 9 is treated with the enolate of ethyl isobutyrate, a mixture of substituted products 10 and 11 is produced. Mechanistic details of these reactions are described.