A Novel Synthesis Process of Cholesterol Ester by the Cross-Coupling of Cholesterol and Aroyl Chlorides

Cholesterol is a sterol with a four-membered ring structure and a single hydroxyl group attached to one of the rings. It is the active, raw form of cholesterol. Cholesteryl Ester is the inactive form in which cholesterol is esterified to be transported to target organs. The newly developed process of making bulky esters from unprecedented tertiary alcohols is applied to synthesize cholesterol esters successfully. Although cholesterol is a secondary alcohol, it is a very bulky and interesting compound due to its immense application. Usually, specific enzymes catalyze cholesterol to cholesterol ester. This project aims to develop a cross-coupling chemistry process to synthesize cholesterol esters and see the broader application of those new cholesterol esters in chemical biology. The mixture of cholesterol, sodium tert-butoxide, aroyl chloride, the catalyst PdCl₂ (d^tbpf) complex, and the solvent 1,4-dioxane, when microwaved at 100˚C for 2 hours, works well for the formation of cross-coupling cholesterol ester products in good to high yields.