Compound 2l

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

Synthesis of 2l: 2 (5.0 mg, 0.0020 mmol) and K₃PO₄ (13.0 mg, 0.061 mmol) were added along with a flea micro stir bar to a 4-mL glass vial, which was then sealed with a PTFE/silicone cap under ambient conditions. The vial was then purged and backfilled with N₂ three times before being transferred into the glovebox. In the glovebox, the vial was opened and 150 µL anhydrous DMF was added, followed by 1-thio-b-D-glucose tetraacetate (25.0 mg, 0.069 mmol). The vial was sealed again and set to stir at 400 rpm for 24 hours. The vial was transferred out of the glovebox, and its contents were transferred into an NMR tube for in situ ¹⁹F NMR spectroscopy to ensure nearly quantitative conversion and in situ ¹¹B NMR spectroscopy to ensure structural integrity of the cluster. The crude mixture was then transferred into a 20-mL glass vial and lyophilized for solvent removal. The resulting residue was treated with NaOMe (6.0 mg, 0.11 mmol) in 1 mL MeOH for 2 hours. The volatiles were removed via rotary evaporation. A 1.25 cm x 35 cm glass column was packed with Sephadex G50 medium in water (23 cm packed height), and the crude product mixture containing 2l was loaded onto the column with water. 15 1-2 mL fractions were collected, dried via lyophilization, and subjected to characterization via ¹H, ¹¹B, and ¹⁹F NMR spectroscopy. The pure product fractions as indicated by NMR spectroscopy were combined and dried via lyophilization to obtain an isolated yield of 1.6 mg (17 %). ¹H NMR (400 MHz, D₂O): δ 5.64 – 5.45 (br s, 24H, OCH₂), 4.03 – 3.20 (m, 84H, SCHCH₂OH(CHOH)₃CHO). ¹¹B NMR (128 MHz, D₂O): δ -16.3. ¹⁹F NMR (376 MHz, D₂O): δ -134.3 – -135.6 (m, 24F, -meta), -143.5 (m, 24F, -ortho). HRMS (Q-Exactive Plus): m/z calculated for C₁₅₆H₁₅₆B₁₂F₄₈O₇₂S₁₂ (M^2-), 2304.2772 Da; found, 2304.2769 Da.