Silyl peroxides preparation

Bis(silyl) peroxide, preparation, 776-7 Bis(stannyl)peroxide, peroxide transfer reaction, 825... 

Chlorotetramethyldisiloxane, preparation, 781 Chlorotriorganosilanes, silyl peroxide preparation, 779-83... 

Vinylic lithium reagents (26) react with silyl peroxides to give high yields of silyl enol ethers with retention of configuration. Since the preparation of 26 from vinylic halides (12-37) also proceeds with retention, the overall procedure is a... 

Silyl peroxides containing a vinyl group have also been prepared by the same method. 

Alkyl hydroperoxides can form 2 1 adducts with DABCO. Both nitrogens of DABCO are involved and the resulting adduct contains 2 mol of hydroperoxide per mol of DABCO. Table 4 lists the silyl alkyl peroxides prepared using the DABCO-hydroperoxide adduct techniques. 

Alkyl(chloro)silyl peroxides 8 and alkyl alkoxysilyl peroxides are prepared by the alkyl hydroperoxidation of dichlorodiorganosilane (equations 13-15). 

Carboxylic peroxides are long known and have been extensively employed in mechanistic and preparative applications. This is also valid for acyclic silyl peroxides, particularly the recently much used BTSP, which as a protected H2O2 exhibits marked advantages as oxidizing agent compared to the parent hydrogen peroxide. 

The simple cyclic silyl peroxide, l,l,4,4-teteramethyl-l,4-disila-2,3-dioxane, 75, was prepared by classical synthetic methodology from its corresponding cyclic disilazane 74 and the urea complex of H2O2 (equation 85) . 

Recently another procedure has appeared,4 dealing with the large scale preparation of BTMSPO. The costs and the yield of the two procedures are comparable, calculated on the amount of H2C>2-base complex used, but the present procedure avoids the potential danger of violent decomposition2 of the silylated peroxide during its distillation. 

Early investigations as to determine the utility of the compound, led to the identification of a new procedure for the preparation of bis(trimethyl-silyl)peroxide. ... 

Ketones and carboxylic esters can be a hydroxylated by treatment of their enolate forms (prepared by adding the ketone or ester to LDA) with a molybdenum peroxide reagent (MoOs-pyridine-HMPA) in THF-hexane at -70°C. The enolate forms of amides and estersand the enamine derivatives of ketones can similarly be converted to their a hydroxy derivatives by reaction with molecular oxygen. The M0O5 method can also be applied to certain nitriles. Ketones have also been Qc hydroxylated by treating the corresponding silyl enol ethers with /n-chloroperoxy-... 

N -Fmoc serine benzyl ester 2, which could be prepared as shown or purchased commercially, was smoothly converted to the crystalHne O-methylthiomethyl (MTM) ether 3 in high yield via a Pummerer-Hke reaction using benzoyl peroxide and dimethyl sulfide in acetonitrile [39]. This common intermediate was used to synthesize both 5 and 8 [40]. Both Ogilvie [41] and Tsantrizos [42] had reported that I2 was an effective activator with similar MTM ether substrates. The H promoted nucleosidation reaction between O-MTM ether 3 and bis-silylated thymine 4 produced the nucleoamino acid 5 in 60% isolated yield (100% based on recovered 3). Hydrogenolytic deprotection of the benzyl ester with H2, Pd/C in MeOH gave the thymine-containing nucleoamino acid 6 in quantitative yield. 

Silicon and germanium peroxides TABLE 1. Preparation of silyl hydroperoxides 1... 

Silyl alkyl and silyl aryl peroxides 7 are prepared by reaction of alkyl, aryl or aralkyl hydroperoxides with halosilanes (equation 12). Such reactions are carried out in an inert solvent in the presence of an acid acceptor, such as pyridine, ammonia or a tertiary amine in ether or petroleum ether (Table 3) . ... 

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