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 minutes. A solution of 7-oxo-3β-triisopropylsilyloxychol-5-en-24-oic acid (4) (5.38 g, 9.9 mmoles) in dry THF (16.5 ml) was added dropwise over 20 minutes 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 minutes and extracted with CH2Cl2 (three times). The combined s 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: δ0.70 (two peaks, 18-Me); 5.14 & 5.20 (6-H) The mixture was used directly in the next reaction (Example 5).

Provenance & Evidence