Chemo-, Regio-, and Enantioselective Rhodium-Catalyzed Allylation of Pyridazinones with Terminal Allenes.

The rhodium-catalyzed addition of pyridazinones to terminal allenes furnished the corresponding branched N2-allylated products in good yields with high regio- and enantioselectivities. A broad functional group compatibility was observed, and assorted synthetic transformations of the N-allylpyridazinones led to the preparation of a small library of N2-functionalized pyridazinones. Labeling experiments with deuterated substrates provided insights into the underlying reaction mechanism.