Stereoconvergent synthesis of enantiopure (-)-trans-lauthisan. Building kit for medium ring oxacycle construction and contrathermodynamic epimerization at allylic carbon C(8) via “invisible”, E-configurated medium ring olefin
作者:H.M.R Hoffmann、Arndt Brandes
DOI:10.1016/0040-4020(94)00960-3
日期:1995.1
Starting once more from simple, acyclic, functionalized α,α′-chiral, disecondary ethers we have prepared enantiomericallypure (-)-trans-lauthisan (which is thermodynamically less stable than its cis-epimer). During a Pd(0) catalyzedcyclization a strained E-configurated, 8-membered allylic ether (as an η2 palladiumcomplex) is believed to be a reactive intermediate, in which the oxygen of the allylic