Trans-Metal-Trapping Meets Frustrated-Lewis-Pair
Chemistry: Ga(CH<sub>2</sub>SiMe<sub>3</sub>)<sub>3</sub>‑Induced
C–H Functionalizations
Marina Uzelac
Alan R. Kennedy
Eva Hevia
10.1021/acs.inorgchem.7b00549.s001
https://acs.figshare.com/articles/journal_contribution/Trans-Metal-Trapping_Meets_Frustrated-Lewis-Pair_Chemistry_Ga_CH_sub_2_sub_SiMe_sub_3_sub_sub_3_sub_Induced_C_H_Functionalizations/4987214
Merging two topical
themes in main-group chemistry, namely, cooperative bimetallics and
frustrated-Lewis-pair (FLP) activity, this Forum Article focuses on
the cooperativity-induced outcomes observed when the tris(alkyl)gallium
compound GaR<sub>3</sub> (R = CH<sub>2</sub>SiMe<sub>3</sub>) is paired
with the lithium amide LiTMP (TMP = 2,2,6,6-tetramethylpiperidide)
or the sterically hindered N-heterocyclic carbene (NHC) 1,3-bis(<i>tert</i>-butyl)imidazol-2-ylidene (I<sup><i>t</i></sup>Bu). When some previously published work are drawn together with
new results, unique tandem reactivities are presented that are driven
by the steric mismatch between the individual reagents of these multicomponent
reagents. Thus, the LiTMP/GaR<sub>3</sub> combination, which on its
own fails to form a cocomplex, functions as a highly regioselective
base (LiTMP)/trap (GaR<sub>3</sub>) partnership for the metalation
of N-heterocycles such as diazines, 1,3-benzoazoles, and 2-picolines
in a trans-metal-trapping (TMT) process that stabilizes the emerging
sensitive carbanions. Taking advantage of related steric incompatibility,
a novel monometallic FLP system pairing GaR<sub>3</sub> with I<sup><i>t</i></sup>Bu has been developed for the activation
of carbonyl compounds (via CO insertion) and other molecules
with acidic hydrogen atoms such as phenol and phenylacetylene. Shedding
new light on how these non-cocomplexing partnerships operate and showcasing
the potential of gallium reagents to engage in metalation reactions
or FLP activations, areas where the use of this group 13 metal is
scant, this Forum Article aims to stimulate more interest and activity
toward the advancement of organogallium chemistry.
2017-05-09 17:24:07
compound
steric
Forum Article
group 13 metal
activation
reagent
t Bu
Trans-Metal-Trapping Meets Frustrated-Lewis-Pair Chemistry
acidic hydrogen atoms
TMT
metalation
lithium amide LiTMP
CH 2 SiMe 3
partnership
NHC
novel monometallic FLP system pairing GaR 3