Oxidations by methyl(trifluoromethyl)dioxirane. 5. Conversion of alcohols into carbonyl compounds

Continued Progress towards Efficient Functionalization of Natural and Non‐natural Targets under Mild Conditions: Oxygenation by C−H Bond Activation with Dioxirane

“…Analysis of oxygen rebound trajectories shows that both dynamically concerted and stepwise mechanisms can be present . This mechanistic scenario had been previously suggested by us . The latter pathway presents several features in common with the selective hydroxylation of alkanes by cytochrome P450; wherein a main insertion process competes with a pathway involving the production of cationic species .…”

“…Exemplary transformations are the oxidation of molecules containing atoms bearing lone pairs like sulfides, sulfoxides, and amines (transformation 2 and 9) . Also, O‐insertion into the C−H bond of various functional groups such as secondary or primary alcohols (transformation 7), into the Si−H bond of silanes (transformation 5), and conversion of epoxy alcohol into the corresponding carbonyl compounds (transformation 6) were shown to be possible …”

Preparation of 1,3‐Dizinc Compounds by a Boron–Zinc Exchange

“…Further investigations into the synthesis, structure, and reactivity of 1,3-dizinc compounds are currently sis of an iodolyzed reaction mixture aliquot). Dicthylthiophenylhorane 3 [3] ( I I 40 g. 64 mmol) was added. The crude reaction mixture was purified by distillation (b. p. 31 C' 0.7mmHg) to give 4b (8.35g. 49mmol.…”

“…53% yield) as it colorless liquid. 1.3-Bis(diethylboryl)2-butylpropane Sb: The iillylic borane 4b (2.15 g, 12.9 mmol) prepared as described above was treated with diethylborane methyl sulfide complex [3] (1.17 g. I I! 9 mmol) for 2 h at 25 C. The unconverted diethylhorane and methyl wlfide was distilled off to leavc crude 5 b (2.49 g.…”

Oxidation of natural targets by dioxiranes. Part 6: on the direct regio- and site-selective oxyfunctionalization of estrone and of 5α-androstane steroid derivatives

“…Quite likely, the C-12 ketone derives from the fast consecutive oxidation of the initially formed sec-alcohol C12H-OH. 17 Actually, in dioxirane oxidation of steroids, 2-4 it is rarely observed that ketogenesis from unactivated methylene CH 2 moieties competes efficiently with the amply favored hydroxylation at tertiary C-H's (a common trait of dioxirane O-insertion into alkane bonds). 3,4b,18 Our results suggest that the presence of an acetoxy function at the C-6 position in the substrate may significantly affect the selectivity of the dioxirane oxyfunctionalization.…”