Intramolecular nucleophilic carbonyl trapping of alpha-ketenyl radicals by an amino group.
Free-radical carbonylation of omega-alkynylamines with tributyltin hydride gives a mixture of alpha-methylene lactams and alpha-stannylmethylene lactams. Nucleophilic addition of an internal amino group to the carbonyl group of alpha-ketenyl radicals is proposed as the cyclization step. The subsequent unusual 1,4-H shift from the resulting 1-hydroxyallyl radical, followed by elimination of the beta-tributyltin radical leads to the formation of alpha-methylene lactams.
Tojino
Mami
M
Department of Chemistry, Faculty of Arts and Sciences, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
Uenoyama
Yoshitaka
Y
Fukuyama
Takahide
T
Ryu
Ilhyong
I
D000588:Amines / Q000138:chemical synthesis*; D003500:Cyclization; D005030:Ethylenes / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D014220:Trialkyltin Compounds / Q000737:chemistry
D000588:Amines; D005030:Ethylenes; D005609:Free Radicals; D007659:Ketones; D014220:Trialkyltin Compounds; C011559:tributyltin; C008223:ketene