Unlocking copper catalysis with nitro compounds: Synthesis of functionalized allylboranes from allylic nitroalkanes

A copper-catalyzed borylation of allylic nitroalkanes is reported. The method, which exploits the high versatility of the nitroalkane precursors, tolerates a variety of functional groups and allows a straightforward access to diversely substituted allylboronic esters in high yields. This unprecedented reactivity towards copper complexes has been further exploited in the synthesis of a number of γ fluoroallyl boronic esters starting from readily available α fluoroallyl nitroalkanes, as well as in various post-functionalizations towards synthetically useful building blocks. Both the reaction mechanism and the chemoselectivity have been rationalized experimentally and through DFT calculations.