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Deprotonation of a Hydridoborate Anion
Author(s) -
Landmann Johannes,
Keppner Fabian,
Hofmann Daniel B.,
Sprenger Jan A. P.,
Häring Mathias,
Zottnick Sven H.,
MüllerBuschbaum Klaus,
Ignat'ev Nikolai V.,
Finze Maik
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201611899
Subject(s) - chemistry , deprotonation , nucleophile , medicinal chemistry , steric effects , imine , borohydride , yield (engineering) , nucleophilic addition , hydrolysis , alkali metal , reagent , boron , ion , stereochemistry , organic chemistry , catalysis , materials science , metallurgy
The first deprotonation of a borohydride anion was achieved by treatment of [BH(CN) 3 ] − with strong non‐nucleophilic bases, which resulted in the formation of alkali‐metal salts of the tricyanoborate dianion B(CN) 3 2− in up to 97 % yield and 99.5 % purity. [BH(CN) 3 ] − is less acidic than (Me 3 Si) 2 NH but a stronger acid than i Pr 2 NH. Less sterically hindered, more nucleophilic bases such as PhLi and MeLi mostly attack a CN group under formation of imine dianions [RC(N)B(CN) 3 ] 2− , which can be hydrolyzed to ketones of the [RC(O)B(CN) 3 ] − type. The boron‐centered nucleophile B(CN) 3 2− reacts with CO 2 and CN + reagents to give salts of the [B(CN) 3 CO 2 ] 2− dianion and the tetracyanoborate anion [B(CN) 4 ] − , respectively, in excellent yields.