Manganese group transfer

A group transfer tandem addition of bromotrichloromethane to diallyl amine 157 has been reported [95SC3529]. The radical reaction can be initiated using either azobisisobutyronitrile (AIBN) or manganese(III) acetate electrochemically. It should be noted that the cis diastereomer is formed as the major product. 

Chromium and Manganese Oxo, Imido, and Nitrido Group Transfer Reagents... 

Zdilla MJ, Abu-Omar MM (2006) Mechanism of catalytic aziridination with manganese corrole the often postulated high-valent Mn(V) imido is not the group transfer reagent. J Am Chem Soc 128(51) 16971-16979... 

As shown in the manganese- and ruthenium-catalyzed intermolecular nitrene insertions, most of these results supposed the transfer of a nitrene group from iminoiodanes of formula PhI=NR to substrates that contain a somewhat activated carbon-hydrogen bond (Scheme 14). Allylic or benzylic C-H bonds, C-H bonds a to oxygen, and very recently, Q spz)-Y bonds of heterocycles have been the preferred reaction sites for the above catalytic systems, whereas very few examples of the tosylamidation of unactivated C-H bonds have been reported to date. 

The coordination chemistry of (phenoxyl)manganese complexes is rather more complicated because both metal- and ligand-centered electron-transfer processes are accessible in the normal potential range. The phenolato precursors are known to exist with manganesc(II), (III), and even (IV). In fact, three phenolato groups strongly stabilize the Mn(IV) oxidation state. 

One possible mechanism for the oxidation of Mn(II) on an oxide surface is shown in Figure 2. The binding of Mn(II) to the surface may facilitate the electron transfer from Mn(II) to 02 (32). The surface groups on the metal oxide, if appropriately cooordinated, will exert a repulsive effect on the electron in the manganese dz orbital, making it easier for the 02 bound to the manganese atom to remove this electron. The nature of the products was not characterized so the overall reaction stiochiometry is unknown. 

Although the Sharpless catalyst was extremely useful and efficient for allylic alcohols, the results with ordinary alkenes were very poor. Therefore the search for catalysts that would be enantioselective for non-alcoholic substrates continued. In 1990, the groups of Jacobsen and Katsuki reported on the enantioselective epoxidation of simple alkenes both using catalysts based on chiral manganese salen complexes [8,9], Since then the use of chiral salen complexes has been explored in a large number of reactions, which all utilise the Lewis acid character or the capacity of oxene, nitrene, or carbene transfer of the salen complexes (for a review see [10]). 

Photolysis of cationic alkoxycarbene iron complexes [193] or alkoxycarbene manganese complexes [194] has been used to replace carbonyl groups by other ligands. The alkylidene ligand can also be transferred from one complex to another by photolysis [195], Transfer of alkylidene ligands occurs particularly easily from diaminocarbene complexes, and has become a powerful synthetic method for the preparation of imidazoline-2-ylidene complexes [155,196]. 

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