Double Lawton S_N2‘Addition to Epoxyvinyl Sulfones:  Selective Construction of the Stereotetrads of Aplyronine A^†

Enantiopure epoxyvinyl sulfones function as templates for the diastereoselective construction of the three stereotetrads of aplyronine A. Lawton S_N2‘ addition of 3,5-dimethylpyrazole followed by its displacement in an alcohol-directed Lawton S_N2‘ reaction establishes the required product stereochemistry with high selectivity.