β-Lactam-Forming Photochemical Reactions of N-Trimethylsilylmethyl- and N-Tributylstannylmethyl-Substituted α-Ketoamides

• Published in: Journal of organic chemistry 2004-02, Vol.69 (4), p.1215-1220
• Main Authors: Wang, Runtang, Chen, Chuanfeng, Duesler, Eileen, Mariano, Patrick S, Yoon, Ung Chan
• Format: Article
• Language: English
• Subjects: Amides - chemistry; beta-Lactams - chemical synthesis; beta-Lactams - chemistry; Chemistry; Exact sciences and technology; Heterocyclic compounds; Heterocyclic compounds with n hetero atom and also o and/or s, se, te hetero atoms; Heterocyclic compounds with only one n hetero atom and condensed derivatives; Ketones - chemistry; Magnetic Resonance Spectroscopy; Molecular Structure; Organic chemistry; Photochemistry; Preparations and properties; Trialkyltin Compounds - chemistry; Trimethylsilyl Compounds - chemistry
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo030343q

Two mechanisms have been proposed for the β-lactam-forming photochemical reactions of α-ketoamides. One, suggested by Aoyama, involves excited-state H-atom abstraction while the other, put forth by Whitten, follows a sequential SET-proton-transfer route. The photochemical properties of N-trimethylsilylmethyl- and N-tributylstannylmethyl-substituted α-ketoamides were explored in order to gain information about the mechanism of this process and to develop a regioselective method for β-lactam formation. The results of this effort show that (1) photoreactions of N-trimethylsilylmethyl-substituted α-ketoamides proceed by competitive H-atom abstraction and sequential SET-desilylation pathways and (2) a sequential SET-destannylation pathway is preferentially followed in photochemical reactions of the tributylstannylmethyl-substituted α-ketoamides.