(3aS,4S,6aR)-2,2-Dimethyl-3a,6a-dihydro-4H-cyclopenta[d][1,3]dioxol-4-ol → (3aR,6aR)-2,2-dimethyl-hexahydrocyclopenta(d)(1,3)dioxol-4-one

Beteiligte Stoffe

Reaktionsschritte

(3aS,4S,6aR)-2,2-dimethyl-4,6a-dihydro-3aH-cyclopenta[d][1,3]dioxol-4-ol (1-1) (10 g, 64.0 mmol, 1 equiv) was dissolved in MeOH (200 mL), the system was placed under nitrogen and 10% Pd/C (681 mg, 6.4 mmol, 0.1 equiv) was carefully added. The resulting mixture was stirred under a H2 atmosphere (1 atm) until disappearance of the starting material as monitored by LC-MS analysis. Hydrogen was removed followed by filtration through a celite plug and washing of the solids with MeOH (4×75 mL). The filtrate was concentrated and the residue was purified via flash chromatography on a 120 g silica gel column (gradient elution 0 to 50% ethyl acetate in hexanes) to yield (3aR,6aR)-2,2-dimethyldihydro-3aH-cyclopenta[d][1,3]dioxol-4(5H)-one (1-2) as a white fluffy solid and (3aS,4S,6aR)-2,2-dimethyltetrahydro-3aH-cyclopenta[d][1,3]dioxol-4-ol (1-3) as a colorless oil. 1H NMR (1-2) (500 MHz, CDCl3): δ 4.84 (t, J=4.8 Hz, 1H); 4.19 (d, J=5.2 Hz, 1H); 2.65-2.53 (m, 1H); 2.33-2.23 (m, 2H); 2.11-2.01 (m, 1H); 1.43 (s, 3H); 1.38-1.31 (m, 3 II). 1H NMR (1-3) (400 MHz, CDCl3): δ 4.61 (t, J=5.3 Hz, 1H); 4.40 (t, J=5.6 Hz, 1H); 3.88-3.77 (m, 1H); 2.43 (d, J=9.9 Hz, 1H); 1.93-1.75 (m, 2H); 1.70-1.55 (m, 1H); 1.49 (s, 3H); 1.47-1.35 (m, 1H); 1.34 (s, 3H).

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