Enantioselective Cross-Coupling of meso-Epoxides with Aryl Halides

Zhao, Y., and D. Weix. Enantioselective Cross-Coupling of Meso-Epoxides With Aryl Halides. J. Am. Chem. Soc., 3240.
Abstract The first enantioselective cross-electrophile coupling of aryl bromides with meso-epoxides to form trans-β-arylcycloalkanols is presented. The reaction is catalyzed by a combination of (bpy)NiCl2and a chiral titanocene under reducing conditions. Yields range from 57 to 99% with 78–95% enantiomeric excess. The 30 examples include a variety of functional groups (ether, ester, ketone, nitrile, ketal, trifluoromethyl, sulfonamide, sulfonate ester), both aryl and vinyl halides, and five- to seven-membered rings. The intermediacy of a carbon radical is strongly suggested by the conversion of cyclooctene monoxide to an aryl [3.3.0]bicyclooctanol.
Keywords alcoholsbond formationcatalyzed radical reactionscomplexesdesymmetrizationelectron-transferkinetic resolutionligandolefinsorganic-synthesis
DOI 10.1021/jacs.5b01909