3.1.1. Synthesis of Compounds **5b–d**

General procedure. To a stirred mixture of sodium hydride (3 mol equiv), washed with hexane (3 × 15 mL), and diethyl carbonate (4 mol equiv) in 50 mL of tetrahydrofuran (THF), the corresponding substituted acetophenone (1 mol equiv) was added dropwise over 30 min. The reaction mixture was refluxed for 4 h, and then poured into ice water, acidified with 5 mL of glacial acetic acid, and extracted with EtOAc (3 × 100 mL). The combined organic phase was washed with saturated sodium bicarbonate, brine, and water, and then dried over anhydrous Na2SO<sup>4</sup> and evaporated in vacuo. The crude products were purified by silica gel column chromatography eluting with dichloromethane to afford **5b–d**. The yields of **5b, 5c,** and **5d** were 80%, 89%, and 92%, respectively.
