a gentle stream of He (or Ar) gas through the mixture. Just before starting the addition of the solid inorganic peroxide, a slight vacuum (650–700 mmHg) is applied to the last trap. Shortly after the addition is initiated, the end two-ways adaptor is switched to insert the main collection flask, and during 6–8 min approximately 12 mL of yellow solution of TFD in TFP is collected, having dioxirane concentrations ranging from 0.5 to 0.8 M; 1H NMR (CF3COCH3, Me4Si, −20 °C) 6 1.97 (s). Cold solutions of TFP can be dried briefly over MgSO4 (Analar grade), quickly filtered, and stored over 5Å molecular sieves at −20 °C (keep well protected from light). Provided that care is exercised in using extra clean glassware (before drying, for final wash we use 0.01% Na2H2EDTA in bidistilled water) and that trace metals and other impurities are carefully excluded, only minor loss of dioxirane content of solutions is observed (e.g., 56% during 48 h, at −20 °C). The expensive TFP solvent can be recovered from decomposed dioxirane solutions by low-temperature fractional distillation (bp 22 °C) through an efficient column. Example oxidation procedure (13) A solution of TFD (4.60 mL, 0.50 M, 2.30 mmol) in trifluoroacetone/CH2Cl2 (2:1 v/v) at –20 ° was added to a solution of adamantane (136 mg, 0.100 mmol) in CH2Cl2 (5 mL) also at –20 °, while stirring vigorously magnetically. The progress of the reaction was followed by GLC analysis, which indicated that 97% of the adamantane was converted to its hydroxylated products in 40 minutes. Removal of the solvent on a rotary evaporator (–20 °, 15 mmHg) afforded a mixture of the 1,3-dihydroxyadamantane (156 mg, 91%) and the monohydroxy adamantane (4.6 mg, 3%). Spectral data for 1,3-dihydroxyadamantane is as follows. IR (KBr): 3275 (O-H), 2930 and 2851 (C-H), 1453, 1135, 1027, 968, 911, 801 cm−1. 1H NMR (CDCl3): 1.50 (m, 2 H), 1.62 (apparent d, 8 H), 1.65 (s, 2 H), 2.23 (m, 2 H), 4.88 (OH). References Organic reactions