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A Stable but Highly Reactive Phosphine‐Coordinated Borenium: Metal‐free Dihydrogen Activation and Alkyne 1,2‐Carboboration
Author(s) -
Devillard Marc,
Brousses Rémy,
Miqueu Karinne,
Bouhadir Ghenwa,
Bourissou Didier
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201500959
Subject(s) - heterolysis , chemistry , electrophile , alkyne , reactivity (psychology) , cationic polymerization , frustrated lewis pair , intramolecular force , boranes , medicinal chemistry , phosphine , stereochemistry , carbene , reactive intermediate , bond cleavage , lewis acids and bases , polymer chemistry , boron , organic chemistry , catalysis , medicine , alternative medicine , pathology
Borenium cations have been found to be valuable analogues of boranes as a result of their cationic character which imparts high electrophilicity. Herein, we report the synthesis, characterization, and reactivity of a new type of borenium cation employing a naphthyl bridge and a strong intramolecular P→B interaction. The cation reacts with H 2 in the presence of P t Bu 3 (frustrated Lewis pair (FLP) approach) but also on its own. The mechanism of the reaction between the borenium cation and H 2 in the absence of P t Bu 3 has been investigated using deuterium‐labeling experiments and DFT calculations. Both experiments and calculations imply the side‐on coordination of H 2 to the B center, followed by heterolytic splitting and BC bond cleavage. An uncommon syn 1,2‐carboboration has also been observed upon reaction of the borenium ion with 3‐hexyne.