Ortho-C-H Benzylation of Aryl Imines with Benzyl Phosphates under Cobalt-Pyphos Catalysis.
Ortho-C-H benzylation of aryl ketimines with benzyl phosphates is achieved with the aid of a catalytic system consisting of a cobalt(II) salt, a phosphine/pyridine bidentate ligand, and a Grignard reagent under room-temperature conditions, affording a variety of diarylmethanes bearing o-acetyl or -acyl groups in moderate to good yields. Owing to the versatility of the o-acetyl group, the reaction opens useful synthetic routes to polycyclic compounds such as unsymmetrical anthracene, anthracenone, and anthraquinone derivatives.
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.
Wengang
W
Xu
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.
Rupankar
R
Paira
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.
Naohiko
N
Yoshikai