A Single-Step Synthesis of 4-Oxazolin-2-ones and Their Use in the Construction of Polycyclic Structures Bearing Quaternary Stereocenters
作者:Blanca M. Santoyo、Carlos González-Romero、Omar Merino、Rafael Martínez-Palou、Aydeé Fuentes-Benites、Hugo A. Jiménez-Vázquez、Francisco Delgado、Joaquín Tamariz
DOI:10.1002/ejoc.200900114
日期:2009.5
for the synthesis of 4-oxazolin-2-ones by a one-pot MW-promoted condensation of α-ketols and isocyanates is reported. An alternative thermal approach using the same starting materials is also described. These cyclic enamides were efficient nucleophiles, reacting with Michael acceptors and prenyl bromide to give a variety of polycyclicstructuresbearing one or two quaternarystereocenters. The selectivity
Regioselective 1,3-Dipolar Cycloaddition Reactions of 4-Methylene-2-oxazolidinones with Benzonitrile Oxide
作者:Rebecca Newton、G. Paul Savage
DOI:10.1071/ch08111
日期:——
two steps by cyclizing O-propargyl carbamates, which in turn were prepared from propargyl alcohols and phenyl isocyanate. The 4-methylene-2-oxazolidinones underwent a 1,3-dipolar cycloaddition reaction with benzonitrileoxide to give the corresponding spiro heterocycles. Where the substitution pattern on the oxazolidinone engendered facial asymmetry, the cycloadditon reaction proceeded with 5:1 selectivity
behaviour of substituted 1,3-oxazolidin-2-ones (1) and 1,3-oxazolin-2-ones (2) on treatment with acid is reported. Electrophylic addition of iminium cations to 1,3-oxazolin-2-onic monomers occurs, yielding the kinetically preferred dimers (3). The elimination pathway to 3 is in direct competition with the formation of the cyclodimerisation products resulting from a thermodynamicallycontrolled process.
Divergent Pd-catalyzed Functionalization of 4-Oxazolin-2-ones and 4-Methylene-2-oxazolidinones and Synthesis of Heterocyclic-Fused Indoles
作者:Daniel Yescas-Galicia、Rodrigo A. Restrepo-Osorio、Ailyn N. García-González、Roberto I. Hernández-Benítez、José C. Espinoza-Hicks、Carlos H. Escalante、Edson Barrera、Blanca M. Santoyo、Francisco Delgado、Joaquín Tamariz
DOI:10.1021/acs.joc.2c01563
日期:2022.10.7
Palladium-catalyzed functionalization was presently performed on two building blocks: 4-oxazolin-2-ones and 4-methylene-2-oxazolidinones. Direct Heck arylation of 4-oxazolin-2-ones led to a series of 5-aryl-4-oxazolin-2-ones, including analogues with N-chiral auxiliary, in an almost quantitative yield. The Pd(II)-catalyzed homocoupling reaction of 4-oxazolin-2-ones provided novel heterocyclic across-ring