Silyl Tether-Assisted Photooxygenation of Electron-Deficient Enaminoesters: Direct Access to Oxamate Formation.
J Org Chem
; 88(1): 172-188, 2023 01 06.
Article
em En
| MEDLINE
| ID: mdl-36516444
ABSTRACT
Photooxygenation reactions of electron-deficient enaminoesters bearing an oxophilic silyl tether at the α-position of the nitrogen atom using methylene blue (MB) were explored to develop a mild and efficient photochemical strategy for oxidative C-C double bond cleavage reactions via singlet oxygen (1O2). Photochemically generated 1O2, through energy transfer from the triplet excited state of MB (3MB*) to molecular oxygen (3O2), was added across a C-C double bond moiety of enaminoesters to form perepoxides, which rearranged to form dioxetane intermediates. The cycloreversion of the formed dioxetane via both C-C and O-O bond cleavage processes led to the formation of oxamates. Importantly, contrary to alkyl group tether-substituted electron-deficient enaminoesters that typically disfavor photooxygenation, the silyl tether-substituted analogues undergo this photochemical transformation efficiently with the assistance of a silyl tether, which facilitates formation of the perepoxide. The observations in this study provide useful information about photosensitized oxygenation reactions of unsaturated C-C bonds, and, moreover, this photochemical strategy can be utilized as a mild and feasible method for the preparation of diversely functionalized carbonyl compounds including oxamates.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oxigênio
/
Elétrons
Idioma:
En
Revista:
J Org Chem
Ano de publicação:
2023
Tipo de documento:
Article