Premium
Mechanism of Ligand‐Controlled Regioselectivity‐Switchable Copper‐Catalyzed Alkylboration of Alkenes
Author(s) -
Xu ZhengYang,
Jiang YuanYe,
Su Wei,
Yu HaiZhu,
Fu Yao
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201602610
Subject(s) - xantphos , regioselectivity , chemistry , alkyl , markovnikov's rule , oxidative addition , ligand (biochemistry) , reductive elimination , stereochemistry , medicinal chemistry , catalysis , combinatorial chemistry , organic chemistry , aryl , receptor , biochemistry
Abstract Cu‐catalyzed alkylboration of alkenes with bis(pinacolato)diboron ((Bpin) 2 ) and alkyl halides provides a ligand‐controlled regioselectivity‐switchable method for the construction of complex boron‐containing compounds. Here, we employed DFT methods to elucidate the mechanistic details of this reaction and the origin of the different regioselectivity induced by Xantphos and Cy‐Xantphos. The calculation results reveal that the catalytic cycle mainly proceeds through the migratory insertion of alkenes on Cu‐Bpin complex, the oxidative addition of alkyl halides, and the reductive elimination of a C−C bond. Meanwhile, the rate‐ determining step is the oxidative addition of alkyl halides and the regioselectivity‐determining step is the migratory insertion of alkenes. The bulky cyclohexyl group of Cy‐Xantphos facilitates the approach of the substituents of alkenes to Bpin in the migratory insertion step and thus leads to the Markovnikov products. The less bulky phenyl group on Xantphos prefers keeping the substituents of alkenes away from the Bpin moiety in the migratory insertion step and thus results in anti ‐Markovnikov products.