Stereoselective total synthesis of dinemasone A by double intramolecular hetero-Michael addition (DIHMA)
作者:Gangavaram V. M. Sharma、Gourishetty Srikanth、Pothula Purushotham Reddy
DOI:10.1039/c2ob26396c
日期:——
The first totalsynthesis of dinemasone A, a bioactive metabolite with a spiroketal moiety, is described. The main strategy for the construction of the spiroketal unit involves a double intramolecular hetero-Michael addition (DIHMA) of an ynone moiety. The thus obtained axial–equatorial mono anomeric spiroketal, on spiroepimerization with ZnBr2, was converted into the requisite axial–axial double anomeric
The stereoselective totalsynthesis of dinemasone A has been accomplished. The key reactions, Sharpless asymmetric epoxidation, lithium-mediated epoxy alcohol opening, and double-intramolecular hetero-Michael addition, gave access to dinemasone A from lactic acid esters. The stereochemistry at the spiro carbon was determined using extensive NMR studies.