Copper-catalyzed stereospecific methoxyboration of styrenes enabled by oxygen umpolung with acetal-based peroxides

An oxygen-umpolung-enabled, regioselective and stereospecific copper-catalyzed methoxyboration of styrenes with diborons and acetal-based methyl peroxide has been developed. The use of designed peroxide enables the otherwise difficult two-electron redox event under the borylcopper catalysis, thus delivering the corresponding oxyborated products with high stereospecificity. Combined with the stereospecific post functionalizations of the boron moiety, the copper catalysis can provide facile access to the stereochemically defined, functionality-rich alkyl ether derivatives ubiquitously found in bioactive molecules and functional materials.