Next, the synthesis of requisite butenolide 18 was carried out. Beginning from (R)-TBS-glycidol 14, methodology developed by the Jacobsen group was enlisted to deliver bromobutenolide 17. Thus, treatment of 14 with ynamine 15 (commercially available) in the presence of BF3•OEt2 effects formation of a highly reactive α-silylenamine that reacts in situ with NBS, producing gem-dibromo-γ-lactone 16 (not isolated), which is smoothly eliminated in crude form (treatment with Li2CO3, LiCl, 75°C) to produce 17 in 55% isolated yield overall. This sequence proved to be highly efficient, being performed instead of DMF as the solvent was crucial, as was the implementation of 5 mol% LiCl as an electrolyte to effect voltage stability (other electrolytes and higher loadings of LiCl proved to be highly deleterious to these reactions). The overall sequence from alkenyl iodide 19 to butenolide 18 is notable as succinate serves as an ethylene source to bridge different sp 2components.