Tandem-selective bond cleavage of the lactam nucleus and michael reaction
The reactivity of the β-lactam ring towards nucleophiles has been investigated. Ring-opening reactions were performed on 3-allyl-β-lactams with CH3O–/CH3OH at room temperature and/or reflux. Lactam nucleus isomerization followed by N1–C2 bond cleavage and methanol Michael addition afforded substituted amino esters. The reactivity of the four-membered ring towards nucleophiles was found to depend on the substituents at the lactamic nitrogen and the C3 and C4 atoms. The ring-opening path is highlighted in this report. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)