A New Synthetic Route to (+/-)-Strigol

Article abstract of DOI:10.1021/jo00386a016

A new more facile synthetic route to strigol, a potent weed seed germination stimulant, utilizes as starting material ethyl 4-oxo-2,6,6-trimethylcyclohex-2-ene-1-carboxylate (2), obtained by the condensation of mesityl oxide and ethyl acetoacetate.Compound 2 was converted in six steps in 38percent overall yield to the previously reported strigol intermediate, 1,4-dioxo-7,7-dimethyl-4,5,6,7-tetrahydro-2-indanacetic acid (11).The new approach is based upon inexpensive starting materials and reagents and is suitable for large-scale production.The key features of the synthesis include reduction of enone 2 to olefin 5 with triethylsilane and boron trifluoride etherate and a one-pot conversion of ethyl 2-(bromomethyl)-6,6-dimethyl-3-oxocyclohex-1-ene-1-carboxylate (10) to the diketo acid 11.