Recyclable polymer-supported Pd catalysts for aryl amination reactions

Tetrahedron Letters

Volumn 46, Issue 43, 2005, Pages 7363-7366

  Guinó, Meritxell ^a   Hii, King Kuok ^a  

^a IMPERIAL COLLEGE LONDON   (United Kingdom)

Author keywords

Aryl amination; Palladium; Polymer support

Indexed keywords

BROMOBENZENE; PALLADIUM; PHOSPHINE; POLYMER; TOLUENE;

AMINATION; ARTICLE; CATALYST; COMPLEX FORMATION; HEATING; PHOSPHORUS NUCLEAR MAGNETIC RESONANCE; ROOM TEMPERATURE; STOICHIOMETRY; SYNTHESIS;

EID: 25444506884     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2005.08.122     Document Type: Article

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17. 2. The mixture was heated at 80°C overnight. After cooling, the beads were stirred for a further 2 h and then collected into a sintered (Alltech) tube and subjected to washings as stated in the previous method. The dark brown beads were dried under vacuum at 50°C for 2 h.
18. During the reviewing process, one referee commented on some unusual values presented in Table 1-entries 5 (low P loading), 8 and 9 (high P loadings)-compared to original loading of the polymer beads (given in footnote 'a'). We do not have a reasonable explanation for this at this juncture. Given that the elemental analyses were carried out, in duplicate, by professional services on the same batch of resins, we have no reason to doubt their accuracy. One possibility is that the loading values provided by the commercial supplier were erroneous. The coordination sphere of immobilised Pd is currently being examined by other techniques, and results will be reported in due course.
19. Reactions were performed in parallel in a Radley's 12-placed reaction carousel. Typical catalytic procedure: A reaction tube was charged with bromobenzene (106 μL, 1.0 mmol), aniline (91 μL, 1.0 mmol), sodium tert-butoxide (150 mg, 1.5 mmol) and the appropriate catalyst (2 mol%). Anhydrous toluene (2 mL) was added and the reaction mixture was stirred at 80°C for 24 h. The progress of the reaction was monitored by GC.
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