An efficient asymmetric synthesis of diacylglycerols

A convenient preparation of 1,2-diacyl-sn-glycerol or 2,3-diacyl-sn-glycerol is described starting from allyl bromide. The latter was converted to allyl 4-methoxyphenyl ether, which is dihydroxylated using AD-mix as a catalyst to yield 3-O-(4'-methoxyphenyl)-sn-glycerol or 1-O-(4'-methoxyphenyl)-sn-glycerol in high yield and high optical purity. After diacylation, ceric ammonium nitrate was used to remove the 4-methoxyphenyl group under mild conditions that avoid acyl migration to 1,3-dipalmitoylglycerol. Thus chiral 1,2-diacylglycerol can be prepared from allyl bromide in just four steps in 78% overall yield and high enantiomeric excess. This scheme represents an inexpensive method for the large-scale preparation of chiral 1,2-diacyl-sn-glycerol and 2,3-diacyl-sn-glycerol.