Activation of Marginally Reactive Boron Enolates by MeLi for the Formation of Enol Phosphates and Synthesis of the Δ(9)-THC Intermediate

J Org Chem. 2015 Sep 18;80(18):9192-9. doi: 10.1021/acs.joc.5b01630. Epub 2015 Sep 8.

Abstract

The addition of MeLi to boron enolates produced by the 1,4-addition of Ar2Cu(CN)Li2 to BF3·OEt2-activated enones was followed by the reaction with ClP(O)(OEt)2 to afford the corresponding enol phosphates in moderate to good yields. The scope of this method was examined with sterically hindered or electronically biased enones and/or reagents. This activation of boron enolates was successfully applied to the synthesis of the methyl ether of Δ(9)-tetrahydrocannabinol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Boron / chemistry*
  • Dronabinol / chemical synthesis*
  • Dronabinol / chemistry
  • Indicators and Reagents / chemistry*
  • Lithium / chemistry*
  • Methyl Ethers / chemical synthesis*
  • Methyl Ethers / chemistry
  • Organophosphorus Compounds / chemistry*
  • Phosphates / chemistry*

Substances

  • Indicators and Reagents
  • Methyl Ethers
  • Organophosphorus Compounds
  • Phosphates
  • Dronabinol
  • Lithium
  • Boron