The thermal cyclization of 3,4-diphenylbuta-1,3-dienyl isocyanates 1, generated in situ from the corresponding azides, was investigated using iodine as a catalyst. Diphenylpyridinones 2, phenylnaphthalenes 3, and indenes 4 were produced viaintramolecularringclosure. The nature of the substituents on the phenyl rings was found to be crucial to the distribution of cyclized products 2–4. The mechanism
Intramolecular Dehydrogenative Coupling of 2,3-Diaryl Acrylic Compounds: Access to Substituted Phenanthrenes
作者:Vijay Gupta、V. U. Bhaskara Rao、Tamal Das、Kumar Vanka、Ravi P. Singh
DOI:10.1021/acs.joc.6b00507
日期:2016.7.1
environmentally benign intramolecular dehydrogenative coupling of various 1,2-diarylethylenes for the synthesis of phenanthrenes in excellent yield has been described. This new methodology uses ceric ammonium nitrate (CAN) as a promoter at room temperature and has been extended to intermolecular synthesis of biaryl compounds. The electron transfer from methoxyarene to cerium leads to cationic radical formation