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Table 1 Optimization for the reaction condition
figureb

From: Synthesis of (1E,3E)-1,4-diarylbuta-1,3-dienes promoted by μ-OMs palladium–dimer complex

Entry Catalyst/5% Solvent Base T/°C t/h Yield/%a
1 Pd(OAc)2 Toluene K2CO3 80 36 19
2 Pd2(dba)3 Toluene K2CO3 80 24 11
3 Pd(OAcCF3)2 Toluene K2CO3 80 24 15
4 μ-OMs dimer Toluene K2CO3 80 36 51
5b μ-OMs dimer/PPh3 Toluene K2CO3 80 24 Trace
6 Pd-Xphos Toluene K2CO3 80 24 Mix
7 μ-OMs dimer Toluene K2CO3 120 18 74
8 μ-OMs dimer DMF K2CO3 120 12 52
9 μ-OMs dimer CH3CN K2CO3 120 12 21
10 μ-OMs dimer NMP K2CO3 120 12 50
11 μ-OMs dimer DMSO K2CO3 120 12 48
12 μ-OMs dimer Toluene Li2CO3 120 24 mix
13 μ-OMs dimer Toluene Cs2CO3 120 15 68
14 μ-OMs dimer Toluene K3PO4 120 20 62
15 μ-OMs dimer Toluene Et3N 120 18 70
16c μ-OMs dimer Toluene K2CO3 120 24 65
  1. Reactions were carried under Ar in Schlenk flasks. 1a (0.5 mmol), 2a (0.5 mmol), Pd* (5 mol%), solvent (2 mL), base (2.0 equiv.), 80–120 °C
  2. aIsolated yields
  3. bReaction condition: μ-OMs dimer (0.01 mmol)/PPh3 (0.011 mol) was stirred at room temperature in DCM (1 mL) under Ar for 0.5 h, then 1a (0.5 mmol), 2a (0.5 mmol), toluene (2 mL), K2CO3 (2.0 equiv.) were added and stirred at 80 °C
  4. cThe catalyst loading is 2.5 mol%