Copper catalyzed atom transfer radical addition (ATRA) and [3+2] azide-alkyne cycloaddition have been shown to be very promising methods for the synthesis of small functionalized molecules. A bifunctional initiator, 1,2-bis(bromoisobutyrloxy)ethane (BBiBE) has been utilized as an alkyl halide initiator in the ATRA reactions with a variety of alkenes, including methyl, ethyl, and propargyl acrylate. Additions proceeded efficiently at ambient temperature using [CuII(Me6TREN)Br][Br] catalyst in the presence of UV-light. The resulting diadducts were subsequently converted to diazido species through a facile SN2 reaction with sodium azide in dimethyl formamide (DMF) in moderate to high yields (70-75%). [3+2] Azide-alkyne cycloadditions were catalyzed by copper(II) sulfate pentrahydrate in the presence of terminal alkynes (1-hexyne, 1-octyne, and 3-methyl-1-pentyn-3-ol) to generate the corresponding 1,2,3-triazoles. Following the optimization of the reaction conditions, in particular catalyst loadings, the presented methodology could be extended to other multifunctional initiators (Figure 1).

Synthesis of small functionalized molecules using copper catalyzed atom transfer radical addition (ATRA) and [3+2] azide-alkyne cycloaddition

252nd National Meeting (2016)

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