反应详情

Zinc dust (3 g, 46 mmol) is placed in a flask and heated under vacuum to remove traces of water. DMF (25 mL) is then added under nitrogen atmosphere. Dibromoethane (cat. 0.25 mL) is added and the mixture heated until effervescence occurs. The reaction is allowed to cool to RT over 30 min and chlorotrimethylsilane (cat 0.3 mL) is added, followed after 30 min with (2-iodoethyl)-carbamic acid tert-butyl ester (4.5 g, 16.5 mmol) dissolved in 10 mL of DMF. After 30 min, TLC indicates the iodide has been consumed and Pd2(dba)3 (0.20 g) and tri-o-tolylphosphine (0.30 g) are added, followed by the dropwise addition of 5-(2-benzyloxy-4-iodophenyl)-1,1-dioxo-2-(2-trimethylsilanylethyl)-1,2,5-thiadiazolidin-3-one (5 g, 9.2 mmol) dissolved in 25 mL of DMF. The reaction mixture is stirred for 14 h and then diluted with EtOAc and filtered through Celite. The filtrate is washed with 1M HCl, brine and water, dried over MgSO4, filtered through a short plug of silica and concentrated to afford the title compound as a light yellow oil.

1. temperatureheated under vacuum
2. customto remove traces of water
3. additionDMF (25 mL) is then added under nitrogen atmosphere
4. additionDibromoethane (cat. 0.25 mL) is added
5. temperaturethe mixture heated until effervescence
6. additionchlorotrimethylsilane (cat 0.3 mL) is added
7. customhas been consumed
8. additionPd2(dba)3 (0.20 g) and tri-o-tolylphosphine (0.30 g) are added
9. filtrationfiltered through Celite
10. washThe filtrate is washed with 1M HCl, brine and water
11. dry with materialdried over MgSO4
12. filtrationfiltered through a short plug of silica
13. concentrationconcentrated