title: Highly linear selective cobalt-catalyzed addition of aryl imines to styrenes: reversing intrinsic regioselectivity by ligand elaboration.
abstract: Highly linear selective, imine-directed hydroarylation of styrene has been achieved with cobalt-based catalytic systems featuring bis(2,4-dimethoxyphenyl)(phenyl)phosphine and either 2-methoxypyridine or DBU as a ligand and a Lewis base additive, respectively, thus affording a variety of 1,2-diarylethanes (bibenzyls) in good yields under mild reaction conditions. The triarylphosphine controls the regioselectivity, while the Lewis base significantly accelerates the reaction. Ligand screening and deuterium-labeling studies provide implications about the roles of the ligand and the Lewis base in the crucial C-C reductive elimination step.
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore) http://www3.ntu.edu.sg/home/nyoshikai/yoshikai_group/Home.html.
authors.forename: Wengang
authors.initials: W
authors.lastname: Xu
authors.forename: Naohiko
authors.initials: N
authors.lastname: Yoshikai
keywords: CH activation; alkenes; cobalt; regioselectivity; synthetic methods