Beta-lactams or gamma-lactams by 4-exo-trig or 5-endo-trig anionic cyclisation of lithiated acrylamide derivatives.
Substituted acrylamide derivatives of benzylamine are lithiated alpha to nitrogen by LDA. The benzyllithium thus formed undergoes either 5-endo-trig anionic cyclisation, formally by intramolecular conjugate addition to the acrylamide, to yield 5-membered lactams, or, if the acrylamide bears a beta-electron withdrawing group, 4-exo-trig cyclisation to a beta-lactam.
Department of Chemistry, University of Manchester, Oxford Road, Manchester, UK M13 9PL.
Jonathan
J
Clayden
David W
DW
Watson
Madeleine
M
Helliwell
Mark
M
Chambers
D020106:Acrylamide / Q000737:chemistry*; D000838:Anions / Q000737:chemistry; D018360:Crystallography, X-Ray; D003500:Cyclization; D008094:Lithium / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D013237:Stereoisomerism; D047090:beta-Lactams / Q000138:chemical synthesis* / Q000737:chemistry
D000838:Anions; D009942:Organometallic Compounds; D047090:beta-Lactams; D020106:Acrylamide; D008094:Lithium