1341233-96-2Relevant academic research and scientific papers
Substituent-controlled electrocyclization of 2,4-dienones: Synthesis of 2,3,6-trisubstituted 2H-pyran-5-carboxylates and their transformations
Peng, Wei,Hirabaru, Toshiaki,Kawafuchi, Hiroyuki,Inokuchi, Tsutomu
supporting information; experimental part, p. 5469 - 5474 (2011/11/06)
A facile access to 2,3,6-trisubstituted 2H-pyran-5-carboxylates is developed by employing 2-alkyl-2-enals as reactants with acetoacetates. The reaction involves Knoevenagel condensation followed by a 6π- electrocyclization, in which the presence of the C2 alkyl substituent in the enals favors the formation of (E)-Knoevenagel adducts for the ensuing electrocyclization. The resulting 2H-pyrans are hydrogenated to form 3,4-dihydro-2H-pyrans and converted into the endoperoxides by singlet-oxygen cycloaddition.
