Aryl Bromides and Aryl Chlorides for the Direct Arylation of Benzylic Amines Mediated by Ruthenium(II). Issue 14 (22nd March 2013)

• Record Type: Journal Article
• Authors: Dastbaravardeh, Navid; Schnürch, Michael; Mihovilovic, Marko D.
• Is Part Of: European journal of organic chemistry. Issue 14(2013)
• Page Start: 2878
• Page End: 2890
• Publication Date: 2013-03-22
• Subjects: Homogeneous catalysis -- C–H activation -- Cleavage reactions -- Reaction mechanisms -- Isotope effects; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201300004
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: The ruthenium(II)‐catalyzed sp 3 C–H bond arylation of benzylic amines with aryl halides is reported. In the present method, aryl iodides and, more importantly, also the cheaper aryl bromides and aryl chlorides can be applied as aryl sources. Additionally, the method does not require elaborate manipulations in a glove box and can be carried out in simple screw cap vials. Potassium pivalate proved to be beneficial for the transformation with aryl bromides or iodides as aryl source, but was not required for aryl chlorides. In the latter case, the addition of PPh3 led to high conversion. 3‐Methyl and 3‐phenyl pyridine were established as directing groups, and the substituent in the 3‐position represents a key structural feature for high conversion. The directing group can be cleaved after the transformation, which allows access to diarylmethylamines. Mechanistic studies were carried out and critically compared to mechanistic reports of related transformations. Abstract : The direct arylation of benzylic amines is reported. Two Ru II ‐catalyzed methods are developed and allow the use of aryl bromides/iodides or alternatively aryl chlorides as the aryl source. Thorough substrate‐scope investigations and mechanistic studies are presented. The two protocols proceed by different mechanisms. The required 3‐substituted pyridine directing group is also cleaved effectively.