Compound 2-Li

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Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

In a 20 mL scintillation vial, a stirring Et₂O solution (~10 mL) of 1 (100 mg, 0.102 mmol) was treated with a single equivalent of LiNHDIPP (18 mg, 0.102 mmol). After 5 minutes of stirring, the solution was slowly treated with a single equivalent of LiCH₂Si(CH₃)₃ (10mg, 0.102 mmol), followed by stirring for 30 minutes at room temperature. Volatiles were removed in vacuo to isolate 2-Li (100 mg, 0.098 mmol, 97%). ¹H NMR (300 MHz, C₆D₆, 25 ºC, TMS) δ = 1.46 (d, ³J(H,H) = 6Hz, 36H, iPrCH₃), 4.53 (sept, ³J(H,H) = 6 Hz, 6H, iPrCH), 5.56 (t, ³J(H,H) = 6 Hz, 3H, p-ArH), 7.76 (d, ³J(H,H) = 6 Hz, 6H, m-ArH); ¹³C NMR (300 MHz, C₆D_6, 25 ºC, TMS) δ = 25.90 (iPrCH₃), 27.05 (iPrCH), 117.68 (m-CH), 124.01 (p-CH), 154.19 (i-C), 156.84 (o-C); IR (KBr plate): = 3046 (w), 2957 (vs), 2866 (s), 1581(w), 1460 (s), 1423 (s), 1408 (w), 1315 (s), 1237 (vs), 1202 (s), 1110 (w), 895 (w), 747 (s); analysis (calcd., found for C₆₄H₁₀₀N₄Li₂O₄U): C (62.75, 62.58), H (8.67, 8.51), N (4.30, 4.36).

Alternative preparation of 2-Li. In a 20 mL scintillation vial, an Et₂O solution of 1 (100 mg, 0.102 mmol) was treated with a single equivalent of NH₂DIPP (18 mg, 0.102 mmol) and let stir for 5 minutes. After such time, the solution was treated with two equivalents of LiCH₂TMS (20 mg, 0.204 mmol) slowly, and the solution was allowed to stir for an additional 30 min at room temperature. Excess solvent was removed in vacuo and analysis by ¹H NMR spectroscopy revealed formation of 2-Li in good yield (88 mg, 0.094 mmol, 92%).