Dimethylaluminum methylselenoate

One of the most general methods for synthesis of selenol esters uses dimethylaluminum methylseleno-late (16), which has been found to be a remaiicably efficient and versatile reagent for the conversion of O-alkyl esters to their corresponding methylselenol esters under mild conditions. The reagent (16) is conveniently prepared by heating a toluene solution of trimethylaluminum with powdered selenium for 2 h under reflux. TTie transformation of various esters to selenol esters can be completed within 1 h. Representative results are shown in Scheme 6 (17-23). This method can also be applied to cyclic esters U ) and esters (20)-(23) containing other functional groups. 

Kozikowski and co-worker reported the conversion of 0-alkyl esters to selenol esters using dimethylaluminum methylselenoate (Me2AlSeMe) (Eq. 39) [76]. 

Methylseleno esters are readily available in excellent yields by the reaction of Dimethylaluminum Methylselenolate with O-alkyl esters. These selenoesters will acylate reactive arenes (eq 69) and heterocyclic compounds (eq 70) when activated by CuOTf, a selenophilic Lewis acid. Of the potential activating metal salts tested, (CuOTf)2 QHe is uniquely effective. Mer-cury(ll) or copper(l) trifluoroacetates that are partially organic-soluble, as well as the corresponding chlorides, silver nitrate, and... 

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