Asymmetric Synthesis of Methoxylated Ether Lipids: Total Synthesis of n-3 Polyunsaturated Docosahexaenoic Acid-Like Methoxylated Ether Lipid

J Org Chem. 2022 Nov 4;87(21):14623-14635. doi: 10.1021/acs.joc.2c01991. Epub 2022 Oct 24.

Abstract

The first total synthesis of a docosahexaenoic acid (DHA)-like methoxylated ether lipid (MEL) is reported. This compound constitutes an all-cis methylene skipped hexaene framework identical to that present in DHA, the well-known omega-3 polyunsaturated fatty acid. The polyene C22 hydrocarbon chain, bearing a methoxyl group in the 2-position and R-configuration at the resulting chiral center, is attached by an ether linkage to the pro-S hydroxymethyl group (sn-1 position) of a glycerol backbone. The asymmetric synthesis is highly convergent and based on the polyacetylene approach involving iterative copper-promoted coupling reactions of propargyl bromides with terminal alkynes and semihydrogenation of the resulting hexayne. Starting from enantiopure R-solketal and racemic epichlorohydrin, the targeted MEL was accomplished in an 8.2% yield over eight steps (longest linear sequence) involving an enantio- and diastereopure glyceryl glycidyl ether key C6-building blocks from which the polyynes were constructed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Docosahexaenoic Acids*
  • Ether*
  • Ethyl Ethers
  • Glycerol
  • Glyceryl Ethers

Substances

  • Docosahexaenoic Acids
  • Ether
  • Glyceryl Ethers
  • Glycerol
  • Ethyl Ethers