Hydrochloric Acid → HCID 57267156, compound

Participants

Reaction Steps

A suspension of anhydrous CeCl3 (1.21 g, 4.94 mmoles) was stirred at room temperature in a N2 atmosphere with dry THF (16.5 ml) for 2 hrs. MeMgCl (3N in THF, 16.5 ml) was added dropwise at room temperature, and the suspension was stirred from 30 min. A solution of 7-oxo-3b-triisopropylsilyloxychol-5-en-24-oic acid (4) (5.38 g, 9.9 mmoles) in dry THF (16.5 ml) was added dropwise over 20 min keeping the temperature of the reaction mixture below 20° with a cold H2O bath. After stirring at room temperature for 2 hrs, the reaction mixture was poured carefully with efficient stirring into a mixture of 90% saturated NH4Cl solution and 100 g of ice. The gummy suspension was acidified with 2N HCl, stirred well for 30 min and extracted with CH2Cl2 (three times). The combined extracts were washed with H2O and saturated brine and dried (MgSO4). Evaporation in vacuo gave 5.46 g of crude 5 as a tan foam. NMR(CDCl3) indicated a mixture of 7-isomers: δ 0.70 (two peaks, 18-Me); 5.14 & 5.20 (6-H) The mixture was used directly in the next reaction (Example 5).

Provenance & Evidence