1,3-Diene principle: an alternative pathway for allene deracemization transformation and migratory functionalization

Asymmetric hydrofunctionalization of allenes has emerged as a valuable strategy for synthesizing privileged allyl skeletons. However, existing studies are largely restricted to special terminal allene substrates to avoid formidable deracemization issues. Herein, we present 1,3-diene principle as a new and broadly applicable mechanistic pathway to address this long-standing challenge and beyond. The 1,3-diene principle is demonstrated by the applications to over ten types of unexplored enantioselective transformations of racemic allenes. Stereodivergent synthesis, convergent preparation, and concise access to natural products further highlight the practical value and generality of this paradigm. Remarkably, the 1,3-diene manifold also enables the first allene migratory hydrofunctionalization, breaking the metal walking chemistry limited to alkene substrates. Both experimental results and theoretical calculations support the deracemization route involving 1,3-diene species, opening a new model for allene transformations.