Merging Copper Catalysis with Nitro Allyl and Allyl Sulfone Derivatives: Practical, Straightforward, and Scalable Synthesis of Diversely Functionalized Allyl Boranes

We report here the first example of a copper-catalyzed transformation involving nitro allyl derivatives. This borylation reaction, which exploits the high versatility of the aforementioned precursor, tolerates a variety of functional groups and allows practical, scalable, and highly straightforward access to diversely substituted allylboronic esters in high yields. The method was also extended to allyl sulfones, which provides a very complementary approach, offering additional structural diversity along with improved stereoselectivities. This new reactivity was further exploited to synthesize γ-fluoroallyl boronic esters as well as various synthetically useful building blocks through key post-functionalizations. Both the reaction mechanism and the chemoselectivity were rationalized experimentally and through DFT calculations.