116437-46-8Relevant articles and documents
Organometallic Ring-Opening Reactions of N-Acyl and N-Alkoxycarbonyl Lactams. Synthesis of Cyclic Imines
Giovannini, Arianna,Savoia, Diego,Umani-Ronchi, Achille
, p. 228 - 234 (1989)
The reactions of hexyl- and phenylmagnesium bromides with N-acyl and N-alkoxycarbonyl lactams in tetrahydrofuran at -78 deg C have been performed to determine the factors affecting the regioselectivity.N-Pivaloyl γ- and δ-lactams undergo the ring-opening reactions with both Grignard reagents, whereas on the N-benzoyl γ-lactam a complete selectivity is achieved only with phenylmagnesium bromide.The N-Cbz γ- and δ-lactams preferentially react at the exocyclic carbonyl group, especially with hexylmagnesium bromide.The N-Boc five- to eight-membered lactams undergo the ring-opening reaction to give N-Boc-ω-amino ketones, although the efficiency slightly decreases by increasing the ring size.The deprotection of the N-Boc-ω-amino ketones with trifluoroacetic acid easily affords the corresponding five- to seven-membered cyclic imines.Pyridine alkaloids containing the cyclic imine moiety have been prepared by a modified route, exploiting the more easily available pyridyllithium reagents, instead of the corresponding Grignard reagents.
