Reductive Coupling of Carbonyl-Containing Compounds and Imines Using Reactive Manganese

7 Reductive Coupling of Carbonyl-Containing Compounds and Imines Using Reactive Manganese 

One of the most powerful methods for constructing a carbon-carbon bond is the reductive coupling of carbonyl compounds giving olefins and/or 1,2-diols [71]. Of these methods, the pinacol coupling [72], which was described in 1859, is still a useful tool for the synthesis of vicinal diols. The corresponding products of this reaction can be used as intermediates for the preparation of ketones and alkenes [73]. More importantly, this methodology has been applied to the synthesis of biologically active natural compounds [74]. 

Generally, the reaction is effected by treatment of carbonyl compounds with an appropriate reagent and/or metal complex to give rise to the corresponding 

MnXj Conditions (temp./time) Yield (%) dl/meso 

To date, no report has appeared using manganese metal. We wish to report a mild method for reductive coupling reactions of aryl aldehydes, aryl ketones, andaldimines [100]. 

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Reductive Coupling of Carbonyl-Containing Compounds and Imines Using Reactive Manganese 347 Table 8.22 Reactivity study of Mn on haiides. 

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