We will present the synthesis of a 6-NHC-Cu(I) complex that can catalyzed a wide range of transformations. The first half of the talk will demonstrate that the catalyst can promote the synthesis of substituted allylboronates using allylic aryl ether substrates. The method was discovered by comparison of the chemoselectivities. While developing an asymmetric version, we observed that both E and Z isomers or E/Z mixtures provided the same absolute configuration. This stereoconvergent reaction occurs with high yields (av 86%), high SN2? selectivity (>99:1), and high ee (av 94%) and exhibits wide functional-group tolerance using pure E or Z isomer or E/Z alkene mixtures. In second half of the talk, we will demonstrate that the same catalyst can provide high regiochemical selectivity for copper-catalyzed hydroborations of alkynes. The resulting allylic ester-vinyl boronates undergo highly E-selective homogation reactions with Grignard reagents.

Asymmetric allylic substitutions and regioselective hydroborations using optically active 6-NHC-Cu(I) catalysts

246th National Meeting (2013)

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