210546-04-6Relevant articles and documents
Aryl bromides and aryl chlorides for the direct arylation of benzylic amines mediated by ruthenium(II)
Dastbaravardeh, Navid,Schnuerch, Michael,Mihovilovic, Marko D.
, p. 2878 - 2890 (2013)
The ruthenium(II)-catalyzed sp3 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.. Copyright
Rhodium-catalyzed direct alkylation of benzylic amines using alkyl bromides
Anschuber, Martin,Pollice, Robert,Schnürch, Michael
, p. 127 - 138 (2018/11/23)
Within this contribution, the development and substrate scope evaluation of a direct alkylation protocol of the C(sp3)–H bond of benzylic amines using alkyl bromides is reported. This pyridine-directed method is initiated by elimination of the alkyl bromide to a terminal olefin, which is then the true alkylating agent. Graphical abstract: [Figure not available: see fulltext.].
Mechanistic investigations and substrate scope evaluation of ruthenium-catalyzed direct sp3 arylation of benzylic positions directed by 3-substituted pyridines
Dastbaravardeh, Navid,Kirchner, Karl,Schnuerch, Michael,Mihovilovic, Marko D.
, p. 658 - 672 (2013/02/26)
A highly efficient direct arylation process of benzylic amines with arylboronates was developed that employs Ru catalysis. The arylation takes place with greatest efficiency at the benzylic sp3 carbon. If the distance to the activating aryl ring is increased, arylation is still possible but the yield drops significantly. Efficiency of the CH activation was found to be significantly increased by use of 3-substituted pyridines as directing groups, which can be removed after the transformation in high yield. Calculation of the energy profile of different rotamers of the substrate revealed that presence of a substituent in the 3-position favors a conformation with the CH2 group adopting a position in closer proximity to the directing group and facilitating C-H insertion. This operationally simple reaction can be carried out in argon atmosphere as well as in air and under neutral reaction conditions, displaying a remarkable functional group tolerance. Mechanistic studies were carried out and critically compared to mechanistic reports of related transformations.
