Silver-mediated carbene transfer reactions

Although silver-mediated oxidative decarboxylation was known for years, its application in synthetic chemistry was very limited (107-110). Systematic studies of this chemistry and other silver-mediated oxidation chemistry in homogeneous solution is rare. This result may be due to the inherent difficulties in working with silver catalysts, which include sensitivity to ligand environment and relative inertness toward oxidation. However, these drawbacks may be overcome with carefully tuned reaction conditions and/or supporting ligand systems. Some of the recent successes with silver nitrene and carbene-transfer reactions will be discussed in detail in Sections VI and Vll. 

Silver can mediate oxidation reactions and has shown unique reactivity. In a few cases, namely, nitrene-, carbene-, and silylene-transfer reactions, novel reactivity was found with homogeneous silver catalysts. Some of these reactions are uniquely facilitated by silver, never having been reported with other metals. While ligand-supported silver catalysts were extensively utilized in enantioselective syntheses as Lewis acids, disappointingly few cases were reported with oxidation reactions. Silver-catalyzed oxidation reactions are still underrepresented. Silver-based catalysts are cheaper and less toxic versus other precious metal catalysts. With the input of additional effort, this field will undoubtedly give more promising results. 

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