Synthesis of 2-hydroxy-1,4-oxazin-3-ones through ring transformation of 3-hydroxy-4-(1,2-dihydroxyethyl)-β-lactams and a study of their reactivity
Chemistry - A European Journal, cilt.19, sa.10, ss.3383-3396, 2013 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 19 Sayı: 10
- Basım Tarihi: 2013
- Doi Numarası: 10.1002/chem.201203314
- Dergi Adı: Chemistry - A European Journal
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.3383-3396
- Anahtar Kelimeler: β-lactams, bond cleavage, density functional calculations, oxazin-3-ones, reaction mechanisms, ring expansion
- Boğaziçi Üniversitesi Adresli: Evet
Özet
The reactivity of 3-hydroxy-4-(1,2-dihydroxyethyl)-β-lactams with regard to the oxidant sodium periodate was evaluated, unexpectedly resulting in the exclusive formation of new 2-hydroxy-1,4-oxazin-3-ones through a C3-C4 bond cleavage of the intermediate 4-formyl-3-hydroxy-β-lactams followed by a ring expansion. This peculiar transformation stands in sharp contrast with the known NaIO4-mediated oxidation of 3-alkoxy- and 3-phenoxy-4-(1,2- dihydroxyethyl)-β-lactams, which exclusively leads to the corresponding 4-formyl-β-lactams without a subsequent ring enlargement. In addition, this new class of functionalized oxazin-3-ones was further evaluated for its potential use as building blocks in the synthesis of a variety of differently substituted oxazin-3-ones, morpholin-3-ones and pyrazinones. Furthermore, additional insights into the mechanism and the factors governing this new ring-expansion reaction were provided by means of density functional theory calculations. Expanding horizons: The reactivity of 3-hydroxy-4-(1,2- dihydroxyethyl)-β-lactams with regard to sodium periodate was evaluated, unexpectedly resulting in the formation of new 2-hydroxy-1,4-oxazin-3-ones through a C3-C4 bond cleavage of the intermediate 4-formyl-3-hydroxy-β- lactams followed by a ring expansion. This result is in sharp contrast to the known NaIO4-mediated oxidation of 3-alkoxy- and 3-phenoxy-4-(1,2- dihydroxyethyl)-β-lactams, which leads to the corresponding 4-formyl-β-lactams without a subsequent ring enlargement (see scheme). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.