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DOI: 10.1055/sos-SD-230-00106

Kubota, K.; Ito, H.Science of Synthesis: Advances in Organoboron Chemistry towards Organic Synthesis, (20191227.

In 2008, Ito, Sawamura, and co-workers reported the first copper-catalyzed enantioselective borylative ring-closing reaction, where the silylated allylic carbonates 1 and diboron reagent 2 are converted into the optically active boryl cyclopropane derivatives 3 with high enantioselectivities (Scheme 1).[‌1‌] The best result is obtained with (R,R)-QuinoxP* as the chiral ligand. This reaction presumably proceeds via regioselective addition of the borylcopper species to the silylated alkene, which seems to be facilitated by the silyl group, followed by intramolecular alkyl substitution on the carbon atom bearing the leaving group.

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