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Theoretical mechanism for selective catalysis of ruthenium complex catalyzed hydroboration of terminal alkynes to Z‐vinylboronates
Author(s) -
Sun Chuanzhi,
Liu Mingshu,
Sun Haitao,
Hang Fang,
Sun Nan,
Chen Dezhan
Publication year - 2015
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.24791
Subject(s) - hydroboration , chemistry , alkyne , ruthenium , alkene , catalysis , acetylene , borane , styrene , photochemistry , reaction mechanism , medicinal chemistry , stereochemistry , organic chemistry , copolymer , polymer
Detailed mechanism of the hydroboration of terminal alkynes catalyzed by ruthenium complex was studied using density functional theory. The calculated results suggest that the reaction proceeds in two steps: alkyne rearrangement and catalyst regeneration. Vinylboronate products with E and Z configuration are formed in this reaction. Path A forming Z‐vinylboronate is the preferred pathway. Noncovalent interaction between BH bond and Ru centre determines the preferred pathway of the reaction. The E gap of HOMO‐LUMO for the reactant is lowered with the assistance of ruthenium–borane complex (Ru–Cat) formation. A hypothetical control model using 1, 2‐dimethyl acetylene (internal alkyne) and styrene (terminal alkene) as the reaction substrates was designed. The calculated results suggest that the activation barrier of the rate‐determining process is too high, which make the hydroboration reaction of styrene and 1, 2‐dimethyl acetylene (CH 3 C‐CCH 3 ) hard to occur. The results uncover the selectivity of the ruthenium complex for hydroboration of terminal alkynes. © 2014 Wiley Periodicals, Inc.