Enantioconvergent Synthesis of Tertiary Cyclic Allylboronates Using (Guanidine)copper Complex‐Catalyzed Allylic Borylation

An enantioconvergent synthesis of chiral cyclic allylboronates is demonstrated with racemic allylic bromides using a (guanidine)copper catalyst. The allylboronates were acquired with high γ/α regioselectivities (up to 99:1) and enantioselectivities (up to 99% ee) and could be further transformed into diverse functionalized allylic compounds without erosion of optical purity. Experimental and DFT mechanistic studies indicated an SN2' borylation process catalyzed by a monodentate guanidine‐copper(I) complex via dynamic kinetic asymmetric transformation.

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