Investigations of Steric and Electronic Factors Influencing the Cyclopalladation of meta-Toluidine Analogues

✍ Scribed by Waldo Mossi; Alfred J. Klaus; Paul Rys

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: German
• Weight: 454 KB
• Volume: 75
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19920750807

✦ Synopsis

Abstract

The cyclopalladation of two different types of aniline derivatives is described: the acetylated anilines N‐(3‐methylphenyl)acetamide (2a), 3‐(acetylamino)‐4‐chlorobenzoic acid (2c), and N‐(2‐chlorophenyl)acetamide (2d) are cyclometalated easily with palladium(II) acetate and trifluoroacetic acid to yield the corresponding complexes 4a, 4c, and 4d, respectively, whereas the acetylated meta‐toluidine N‐(2‐chloro‐5‐methylphenyl)acetamide (2b) cannot be metalated at the only accessible site between the acetylamino and the methyl group. This aromatic CH bond can be activated, however, with the second type of meta‐toluidine derivatives: the 2‐chloro‐5, N‐dimethyl‐N‐nitrosoaniline (3b) readily undergoes cyclopalladation to yield the corresponding Pd^II^ complex di‐μ‐trifluoro‐acetato‐bis[3‐chloro‐6‐methyl‐2‐(N‐methyl‐N‐ nitrosoamino)phenyl‐C,__N__O]dipalladium(II) (5b) containing a five‐membered palladacycle with coordination of Pd^II^ at the nitroso N‐atom, which is established by ^15^N‐NMR spectroscopy.