TPAP oxidation sensitivity

Due to the neutral and very mild conditions used in TPAP oxidations, virtually all protecting groups remain unaffected, including the very oxidant-sensitive PMB ethers77 and p-methoxybenzylidene acetals 78 and the very acid-sensitive TMS ethers.76... 

A very mild oxidative transformation of nitro compounds into ketones using tetrapropylam-monium perruthenate (TPAP) has been developed. A stoichiometric amount of TPAP in the presence of A-methylmorpholine A-oxide (NMO) and 4 A molecular sieves (MS).18a As the reaction conditions are neutral and mild, this method is compatible with the presence of other sensitive functionalities (Eq. 6.11). This transformation can be carried out with 10 mol% of TPAP and 1.5 equiv of NMO in the presence of potassium carbonate, 4 A MS, and silver acetate (Eq. 6.12).18b... 

Functional Group and Protecting Group Sensitivity to Oxidation with TPAP... 

Some very mild oxidizing agents are being more and more widely used for the synthesis of very sensitive aldehydes. One of these is known as TPAP (tetra-n-propylammonium perruthen-ate, pronounced tee-pap ). 

F.i. Tetrapropylammonium Perruthenate-Ley Oxidation. Ruthenium derivatives have been used for oxidation reactions. A particularly useful one is TPAP, introduced by Ley for the oxidation of alcohols and called Ley oxidation. 1 2 a very mild oxidizing agent that is compatible with many sensitive... 

Some very mild oxidizing agents are being more and more widely used for the synthesis of very sensitive aldehydes. One of these is known as TPAP (tetra-n-propylammonium perruthe-nate, pronounced tee-pap ). TPAP can he used catalytically, avoiding the large amounts of toxic heavy metal by-products generated by most chromium oxidations. The stoichiometric oxidant in this reaction is NMO (JV-methylmorpholine-N-oxide), which is reduced to the amine, reoxidizing the ruthenium to Ru(VII). 

The oxidation of alcohols with (l,l-dimethylethyl)benzene-sulfenamide is extremely mild and many sensitive functional groups such as epoxides and alkenes are tolerated hy the reaction conditions (eq 5). In the case of alcohol 1, oxidation with tetrapropylammonium perruthenate (TPAP) resulted in only 58% yield and Swern oxidation was unsuccessful. Epimerizable aldehydes such as the protected phenylglycinol 2 do not undergo racemization when oxidized (eq 6). ... 

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