反应详情

A solution of ethyl N-(diphenylmethylene)glycinate (1.71 g, 6.40 mmol) in dry THF (10 ml) was added to a stirred solution of LDA (2M in heptane/THF/ethylbenzene, 3.20 ml, 6.40 mmol) in dry THF (10 ml) at −70° under nitrogen. After stirring at this temperature for 0.75 h, a solution of 5-benzenesulphonyloxy-2-bromomethyl-pyridine [2.00 g, 6.01 mmol; prepared as described by Myers et al, J.Org.Chem. (1996), 61, 813] in dry THF (10 ml) was added. The reaction mixture was stirred at −70° for 1 h then at room temperature for 18 h. The reaction was quenched with water (10 ml) then partitioned between EtOAc (70 ml) and brine (30 ml). The phases were separated and the aqueous phase re-extracted with EtOAc (2×40 ml). The combined organic extracts were washed with brine (10 ml), dried (Na2SO4) and evaporated in vacuo to afford the crude product as a dark oil. Purification by flash chromatography (silica, 60% to 75% Et2O/hexane; applied as DCM solution) afforded the title compound as a tan-coloured solid (2.25 g, 72%). δH (CDCl3) 8.02 (1H, d, J 2.8 Hz, pyr-H(6), 7.72 (2H, d, J˜8 Hz, ortho-Ar—H), 7.59 (1H, t, J˜8 Hz, para-Ar—H), 7.50 (2H, dd, J 8.4, 1.4 Hz, phenyl-H), 7.40-7.27 (8H, ms, Ar and phenyl-H), 7.19 (1H, dd, J 8.5, 2.8 Hz, pyr-H(4), 7.11 (1H, d, J 8.5 Hz, pyr-H(3), 6.67 (2H, br d, J˜8 Hz, phenyl-H), 4.50 (1H, dd, J 9, 4.6 Hz, CH-α), 4.24-4.10 (2H, sym.m. CH2CH3), 3.50-3.33 (2H, m, pyr-CH2), 1.24 (3H, t, J 7.2 Hz, CH2CH3); m/z (ESI) 515 (MH+).

1. stirringThe reaction mixture was stirred at −70° for 1 h
2. waitat room temperature for 18 h
3. customThe reaction was quenched with water (10 ml)
4. customthen partitioned between EtOAc (70 ml) and brine (30 ml)
5. customThe phases were separated
6. extractionthe aqueous phase re-extracted with EtOAc (2×40 ml)
7. washThe combined organic extracts were washed with brine (10 ml)
8. dry with materialdried (Na2SO4)
9. customevaporated in vacuo
10. customto afford the crude product as a dark oil
11. customPurification by flash chromatography (silica, 60% to 75% Et2O/hexane; applied as DCM solution)