Table 2.
entry | R1 | R2 | product | % yieldb | erc |
---|---|---|---|---|---|
1 | Ph | H | 15a | 81 | 95.5:4.5 |
2 | p-CH3O-C6H4 | H | 15b | 84 | 96:4 |
3 | p-Br-C6H4 | H | 15c | 82 | 95:5 |
4 | m-F-C6H4 | H | 15d | 80 | 95:5 |
5 | m-CF3-C6H4 | H | 15e | 82 | 95:5 |
6 | 3-C4H3S | H | 15f | 87 | 95:5 |
7d | C6H11 | H | 15g | 76 | 97:3 |
8d | n-Bu | H | 15h | 73 | 95:5 |
9d | BnOCH2 | H | 15i | 74 | 95.5:4.5 |
10 | Ph | CH3 | 15j | 78 | 95:5 |
11d | n-Bu | CH3 | 15k | 71 | 93:7 |
Reactions were run with 0.25 mmol 14, 0.25 mmol amine, 0.25 mmol glyoxylate, 0.0375 mmol (S)-5j, and 3Å molecular sieves in toluene for 36 h under Ar, followed by flash chromatography on silica gel.
Isolated yield.
Determined by chiral HPLC analysis.
Reactions were run at 0 °C.