A Practical and Modular Construction of C(sp3)-rich Alkyl Boron Compounds

Alkyl boronic acids and esters play an important role in the synthesis of C(sp³) rich medicines, agrochemicals, and other materials. This work describes a new type of transition-metal free mediated transformation to enable the construction of C(sp³)-rich, and sterically hindered alkyl boron reagents in a practical and modular manner. The broad generality and functional group tolerance of this method is extensively examined through a variety of substrates, including synthesis and late-stage functionalization of scaffolds relevant to medicinal chemistry. The strategic significance of this approach, with alkyl boronic acid as a linchpin, is demonstrated through various downstream functionalizations of the alkyl boron compounds. This two-step concurrent cross-coupling approach, resembling formal and flexible alkyl-alkyl couplings, provides a general entry to previously synthetically challenging high Fsp³-containing drug-like scaffolds.