15‐Membered Triolefinic Macrocycles − Catalytic Role of (E,E,E)‐1,6,11‐Tris(arenesulfonyl)‐1,6,11‐triazacyclopentadeca‐3,8,13‐triene Complexes of Palladium(0) in the Presence of Phosphanes

Abstract

The palladium(0) complexes of (E,E,E)‐1,6,11‐tris(arenesulfonyl)‐1,6,11‐triazacyclopentadeca‐3,8,13‐trienes deliver palladium to phosphanes with the generation of high concentrations of catalytically active species such as Pd(PPh3)2. After oxidation of the phosphanes, the palladium is reincorporated into the macrocycle, thus avoiding agglomeration and precipitation. These conclusions were reached by 31P NMR, 19F NMR, and electrospray ionization mass spectrometry studies of telomerization and Tsuji−Trost reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

15-Membered triolefinic macrocycles, their coordination chemistry with transition metals, and the catalytic properties of their palladium metal complexes. A review.

“…After catalysis ends up, if the phosphine is oxidized, palladium(0) reverts to the free macrocycle 1jjj, to be stored as complex 4jjj, thus preventing agglomeration and remaining available for a new reaction, that requires addition of fresh phosphine but not of fresh palladium. The allylation of diphenylamine 33 with cinnamyl carbonate 34 (Scheme 9) in the presence of 4jjj and phosphine in THF at room temperature to give 35 was also monitored 14 by 19 F and 31 P-NMR, the results being consistent with the same mechanistic proposal. Further evidence of the formation of intermediate species PdL n when macrocycles 4 react with phosphines was gained by an ESI-MS study 14 of the reactions between complex 4ggi and several phosphines in THF.…”

“…The allylation of diphenylamine 33 with cinnamyl carbonate 34 (Scheme 9) in the presence of 4jjj and phosphine in THF at room temperature to give 35 was also monitored 14 by 19 F and 31 P-NMR, the results being consistent with the same mechanistic proposal. Further evidence of the formation of intermediate species PdL n when macrocycles 4 react with phosphines was gained by an ESI-MS study 14 of the reactions between complex 4ggi and several phosphines in THF. We have increased the family of our 15-membered macrocycles modifying the olefin precursors with the aim of studying the complexating ability of the new members of the family.…”

“…Thus, we have prepared a large amount of different transition metal macrocyclic complexes ( Table 2). The palladium complexes 4 are obtained either by ligand-exchange using Pd(PPh 3 ) 4 or Pd(dba) 2 as sources of metal 4,6,8,[11][12][13][14][15] or by in situ reduction of PdCl 2 with hydrazine in the presence of the macrocycle. 10 Excellent results …”

“…Henin and coworkers showed 8,14 that the telomerization of butadiene with methanol can be performed with 4aaa and monodentate phosphines, the catalytic species being recycled up to four times by adding fresh phosphine each time (Scheme 9). Moreover, the addition of free macrocycle 1aaa to the catalytic systems formed in situ from palladium sources (Pd(dba) 2 , Pd(OAc) 2 ) associated with phosphines has a stabilizing effect on palladium and allowed the recovery and reuse of the catalyst after addition of fresh phosphine each time.…”

“…This was not possible without added 1aaa. To get information about the real catalytic species in the telomerization reaction in the presence of macrocycle, we undertook mechanistic studies 14 by 19 F-NMR and 31 P-NMR with macrocycle 1jjj and complex 4jjj. The three fluorine atoms show one signal in the ligand 1jjj, whereas the complex 4jjj shows two fluorine signals of relative intensity 1:2.…”