Free-Radical Annelation in the Synthesis of Bicyclic β-Lactams. 7. A One-Pot, Four-Step, Sequential Reaction
Nonfused, alkynyl-β-lactams 10 and 18 react with n-Bu3SnH to give tert-butyl carbaceph-2-em-4-carboxylate (11) and methyl 1-oxahomoceph-3-em-5-carboxylate (19), respectively, in a four-step, sequential radical reaction involving homolytic intermolecular addition, intramolecular hydrogen atom transfer, endo-intramolecular addition, and β-elimination.
Bosch, Eric, and Mario D. Bachi. "Free-radical annelation in the synthesis of bicyclic. beta.-lactams. 7. A one-pot, four-step, sequential reaction." The Journal of Organic Chemistry 58, no. 21 (1993): 5581-5582.
Journal of Organic Chemistry