Transition-Metal-Free Insertion of Diazo Compounds, N-Arylsulfonylhydrazones or Ylides into Organoboronic Acids or Their Derivatives

Abstract Insertion reactions of carbenes or ylides with organoboronic acids or their derivatives have emerged as valuable methods for coupling or homologation of organoboron compounds under metal-free conditions. The crucial steps of these reactions are coordination of the electron-rich carbon centers of the carbene precursors or ylides to the electron-poor boron center, followed by 1,2-migration of the corresponding tetracoordinated boron intermediates. This type of unique transformation provides an efficient method for the construction of C–C or C–X (X = H, B) bonds. Moreover, the C–B bonds generated by such transformations can be utilized as a handle for further derivatization or iterative homologations. In this Account, we summarize the developments in this arena according to the reactive diazo compound, N-arylsulfonylhydrazone or ylide species involved. 1 Introduction 2 Reactions with Diazo Compounds 3 Reactions with N-Arylsulfonylhydrazones 4 Reactions with Ylides 5 Conclusion