Table 1.
| ||||
---|---|---|---|---|
entry | X | product | time (h) | % isolated yield |
1 | Cl | 5 | 94, 94a, 93b | |
2 | Cl | 3 | 96, 86b, 93c | |
3 | Cl | 7 | 39, 68b | |
4 | Br | 3.5 | 56, 64b | |
5 | Cl | 2.5 | 97, 91b, 98d | |
6 | Cl | 5.5 | 85, 81b | |
7 | Cl | 2.5 | 92, 91b | |
8 | Cl | 3 | 97, 98a 98b, 87e, 85f |
|
9 | Br | 6 | 90, 94b | |
10 | Cl | 5 | 84, 97b | |
11 | Br | 5 | 96g, 87b,g | |
12 | Br | 3 | 84, 97b | |
13 | Br | 6 | 91, 94b | |
14 | Br | 7 | 4, 27b | |
15 | Br | 26 | 75, 80b | |
16 | Cl | 22 | 81, 53b | |
17 | Cl | 22 | 43 | |
18 | Cl | 22 | 0 |
General conditions: 0.5 mol % of 1, 1.0 mol % of 2, 3.0 equiv of KOAc, 3.0 equiv of B2(NMe2)4, MeOH (0.2 M), 60 °C for time indicated.
0.5 M MeOH.
Yield from previous method with B2(OH)4 as boron source (ref 15).
Reaction run in a round bottom flask with reflux condensor under argon.
10 mmol reaction run under general reaction conditions.
(1)5.0 mol % of Pd(OAc)2, 10 mol % of 2, 3.0 equiv of KOAc, 60 °C in 2 mL MeOH for 20 min. (2) 3.0 equiv of B2(NMe2)4 dissolved in 5.5 mL of MeOH, 1-chloro-4-fluorobenzene, 60 °C for time indicated.
Yield of isolated boronic acid.
From the acetonide.