Iron-catalyzed tandem carbon–carbon/carbon–oxygen bond formation/aromatization of 2′-alkynyl-biphenyl-2-carbinols: a new approach to the synthesis of substituted phenanthrenes
作者:Krishnendu Bera、Soumen Sarkar、Umasish Jana
DOI:10.1016/j.tetlet.2014.11.073
日期:2015.1
An iron-catalyzed efficientsynthesis of substituted phenanthrenes through tandem intramolecular C–C/C–O bond formations/aromatization of 2′-alkynyl-biphenyl-2-carbinols is reported. This method provides a novel, highlyefficient, and straightforward route to 9,10-substituted phenanthrene in good to excellent yields. The present strategy involves tandem Fe(OTf)3-catalyzed generation of benzylic carbocation
Synthesis of 9,
<scp>10‐Phenanthrenes</scp>
via Rh(
<scp>III</scp>
)‐Catalyzed [4+2] Annulation of
<scp>2‐Biphenylboronic</scp>
Acids with Diazo Compounds
A Rh(III)-catalyzed, transmetalation triggered C—Hactivation/annulation of 2-biphenylboronic acids with diazo compounds from β-keto esters or 1,3-dicarboxylates has been developed, leading to the synthesis of two kinds of 9,10-phenanthrenes. Notably, a rhodacyle was synthesized by treating the rhodium catalyst with stoichiometric amounts of 2-biphenylboronic acids and pyridine, which was further verified