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Mechanism of Palladium‐Catalyzed Spiroannulation of Naphthols with Alkynes: A Density Functional Theory Study
Author(s) -
Luo Xiaoling,
Zhong Kangbao,
Lan Yu
Publication year - 2020
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.202000613
Subject(s) - chemistry , moiety , transition state , reductive elimination , oxidative addition , aryl , density functional theory , palladium , steric effects , chirality (physics) , enantioselective synthesis , deprotonation , catalysis , reaction mechanism , non covalent interactions , ligand (biochemistry) , stereochemistry , photochemistry , computational chemistry , organic chemistry , molecule , hydrogen bond , physics , quantum mechanics , ion , alkyl , nambu–jona lasinio model , chiral symmetry breaking , receptor , biochemistry , quark
Pd‐catalyzed spiroannulation of bromophenylnaphthalenols with acetylenes to achieve asymmetric dearomatization is a powerful way to construct chiral spiro ‐compounds. DFT calculations with the M06 functional have been performed to reveal the mechanism and enantioselectivity of this reaction. After reversible oxidative addition of aryl bromide to Pd(0), acetylene insertion into the Pd−C(aryl) bond is considered to be the rate‐ and enantioselectivity determining step. Subsequent deprotonation and reductive elimination then give the spiroannulation product. The overlay and noncovalent interaction analysis of the critical transition states were used to reveal the origin of the enantioselectivity for this reaction. We found that the axial chirality of the naphthol moiety affects the relative free energies of the corresponding transition states, whereas the enantioselectivity is controlled by the steric repulsion between the naphthol moiety and the ligand.