Iodine → (5R)-2-iodo-6-methyl-7-(2-methylthiazol-4-yl)-5-(triethylsilyloxy)-2,6-heptadiene

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a suspension of ethyltriphenylphosphonium iodide (7.90 g) in THF (150 mL) is added n-butyllithium (7.17 mL, 2.5 M in hexane) at ambient temperature. After disappearance of the solid material, the red solution is cannulated into a vigorously stirred solution of iodine (4.54 g) in THF (150 mL) at −78° C. The resulting dark brown suspension is stirred for 5 minutes and allowed to warm gradually to −30° C. A solution of sodium hexamethyldisilazide (17.3 mL, 1.0 M in THF) is added dropwise to afford a dark red solution. A solution of (3R)-3-(triethylsilyloxy)-4-methyl-5-(2-methylthiazol-4-yl)-pent-4-enal (2.0 g) in THF (10 mL) is slowly added, and stirring is continued at −30° C. for 30 minutes. The reaction mixture is diluted with pentane (100 mL), filtered through a pad of Celite, and concentrated. Purification by flash column chromatography on SiO2 (hexane/ethyl acetate, 15:1) affords the vinyl iodide.

Herkunft & Nachweise