Table 1.
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Product | R | Yield (%)
|
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Catalyst: | (Ph3P)2PdCl2
|
Pd(OAc)2
|
Frech
|
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Method: | A | B | A | B | C | D | ||
3a | n-C3H7 | 37 | 42 | 50 | 52 | 80 | 80 | |
3b | i-C4H9 | 30 | 65 | 67 | 67 | 82 | 81 | |
3c | i-C4H7 | 36 | 56 | 65 | 63 | 75 | 76 | |
3d | c-C6H11 | 32 | 47 | 54 | 57 | 82 | 82 | |
3e | C6H5 | 26 | 60 | 58 | 55 | 78 | 80 | |
3f | 4-CH3C6H4 | 38 | 67 | 66 | 64 | 76 | 74 | |
3g | 4-FC6H4 | 28 | 55 | 62 | 63 | 79 | 77 | |
3h | C6H5CH2 | 22 | 56 | 68 | 68 | 83 | 80 | |
3i | 4-CH3C6H4CH2 | 18 | 48 | 56 | 45 | 75 | 71 | |
3j | 4-CF3OC6H4CH2 | 10 | 25 | 38 | 40 | 74 | 77 |
Method A: Round-bottomed flask, 1.30 mmol each of 1 and 2, 1.42 mmol of N-ethylpiperidine, 1.63 × 10−2 mmol of catalyst, 4 mL of DMF, 140°C, 18 h; Method B: Sealed tube, 1.30 mmol of 1 and 2, 1.42 mmol of N-ethylpiperidine, 1.63 × 10−2 mmol of catalyst, 4 mL of DMF, 140°C, 18 h; Method C: Round-bottomed flask, 1.30 mmol of 1 and 2, 1.42 mmol of N-ethylpiperidine, 1.55 × 10−3 mmol of catalyst, 4 mL of DMF, 140°C, 18 h; Method D: Sealed tube, 1.30 mmol of 1 and 2, 1.42 mmol of N-ethylpiperidine, 1.55 × 10−3 mmol of catalyst, 4 mL of DMF, 140°C, 18 h. All reactions were performed under argon.