Synthesis of N-(triisopropylsilyl)- and N-(tert-butyldimethylsilyl)aldimines and their application in the synthesis of β-lactams

Article abstract of DOI:10.1055/s-1997-1276

A new and efficient synthesis of N-(TIPS)imines and N-(TBDMS)-imines starting from enolizable and non-enolizable aldehydes is described. We tested the reactivity of these imines in the preparation of β-lactams. N-(TBDMS)imines effectively give N-(TBDMS)azetidinones with a trans stereochemistry of the ring substituents, complementing N-(TMS)imines which instead afford cis β-lactams. In contrast, N-(TIPS)imines react with ester enolates in few cases because of the extremely low rate of the ring-closure step, so that a decomposition of enolates occurred.