3731-16-6Relevant articles and documents
Functionalized Cyclopropanes as Versatile Intermediates for the Diversity-Oriented Synthesis of γ-Lactones, γ-Lactams and δ-Lactams
Maximiano, Adrielle P.,Ramos, Giovana S.,Marques, Marcelo V.,Sá, Marcus M.
, (2021/03/18)
A two-step procedure for the preparation of cyclopropanecarboxaldehyde-1,1-diester from a γ,δ-epoxyester and its synthetic versatility are described herein. The epoxide ring-opening/cyclopropanation process occurs in the presence of Mg(ClO 4) 2under heating, resulting in cyclopropanemethanol-1,1-diester in 65% yield. A mild TEMPO-mediated oxidation of this substrate readily generated the corresponding aldehyde in 75% yield, which was applied in the one-pot synthesis of four cyclopropylidene-γ-lactams and three δ-lactams. In addition, vinylcyclopropanes were obtained through the Wittig reaction of the aldehyde with phosphonium salts and used as precursors for tetrahydrofurans.
Influence of ring size on the outcome of sulfide contraction reactions with thiolactams. Isolation of bicyclic ketene S,N-acetals and thioisomuenchnones
Michael, Joseph P.,De Koning, Charles B.,Van der Westhuyzen, Christiaan W.,Fernandes, Manuel A.
, p. 2055 - 2062 (2007/10/03)
Reaction between diethyl bromomalonate and 3-phenylpyrrolidine-2-thione yielded a vinylogous urethane by the Eschenmoser sulfide contraction. However, with 3-substituted piperidine-2-thiones, sulfur was retained in the products, and a range of bicyclic heterocycles, including bicyclic ketene S,N-acetals (2-alkylidene-1,3-thiazolidin-4-ones) and stable thioisomuechnones, was isolated. A novel dimeric ketene S,N-acetal was characterised by X-ray crystallography.
