Catalytic Asymmetric 1,2-Migration/Allylation of Alkynyl Boronate Complexes: A Modular Route to Enantioenriched Skipped 1,4-Dienes

Stereodefined skipped 1,4-dienes are key structural motifs found in a wide range of natural products and bioactive molecules. However, their stereo- and enantioselective syntheses remain a significant challenge. While electrophilic-allylation-triggered 1,2-migration reactions of alkynyl boronate complexes are in principle a straightforward method to produce skipped dienes, such reactions suffer from poor stereoselectivity or undesired regioselectivity. We now report that, through judicious selection of the alkynyl boronate complex, we can achieve a highly regio-, diastereo-, and enantioselective construction of polysubstituted skipped 1,4-dienes via an Ir-catalyzed 1,2-migration/allylation strategy. Furthermore, the resulting alkenylboron species could be intercepted, which provides a gateway to even more challenging tetrasubstituted alkene-containing skipped dienes.