Transition metal-free coupling of 1,3-dipoles and boronic acids as a sustainable approach to C-C bond formation

Livingstone, Keith and Bertrand, Sophie and Kennedy, Alan R. and Jamieson, Craig (2020) Transition metal-free coupling of 1,3-dipoles and boronic acids as a sustainable approach to C-C bond formation. Chemistry - A European Journal, 26 (46). pp. 10591-10597. ISSN 0947-6539

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    Abstract

    The need for alternative, complementary approaches to enable C-C bond formation within organic chemistry is an on-going challenge in the area. Of particular relevance are transformations that proceed in the absence of transition metal reagents. In the current study, we report a comprehensive investigation of the coupling of nitrile imines and aryl boronic acids as an approach towards sustainable C-C bond formation. In situ generation of the highly reactive 1,3-dipole facilitates a Petasis-Mannich-type coupling via a nucleophilic boronate complex. The introduction of hydrazonyl chlorides as a complementary nitrile imine source to the 2,5-tetrazoles previously reported by our laboratory further broadens the scope of the approach. Additionally, we exemplify for the first time the extension of this protocol into another 1,3-dipole, through the synthesis of aryl ketone oximes from aryl boronic acids and nitrile Noxides.