Chapter 4
FLP-Mediated C–H-Activation
Yashar Soltani and Frédéric-Georges Fontaine
Abstract The C–H functionalization of aromatic molecules is a green approach
that allows creating complex molecules from simple reagents. While these transformations are mainly catalysed using transition metal complexes, the main group
molecules, including frustrated Lewis pairs, have been shown to be efficient species to
functionalize C–H bonds. This chapter describes the different approaches and mechanisms that are used to activate C–H bonds using Lewis acidic boron and silicon
species. On the one hand, highly electrophilic cationic boron and silicon species can
activate C–H bonds by an electrophilic addition pathway that generates a Wheland
intermediate that is further deprotonated by a Lewis base. On the other hand, frustrated Lewis pairs act in a concerted way where the Lewis acid activation and the
deprotonation by a base occur simultaneously. In both systems, the nature of the
Lewis acid and Lewis base plays an important role on the activity and the selectivity
of the functionalization reaction.
Keywords C–H activation · Electrophilic addition · Borylation · Silylation ·
Frustrated lewis pairs
Abbreviations
HBPin
4,4,5,5-Tetramethyl-1,3,2-dioxaborolane
HBCat Catecholborane
Pin
Pinacolate
Cat
Catecholate
9-BBN 9-Borabicyclo[3.3.1]nonane
3c-2e
Three-centre two-electron
AIBN
Azobisisobutyronitrile
Ar
ArylY. Soltani · F.-G. Fontaine (B)
Département de Chimie, Université Laval, 1045 Avenue de la Médecine, Québec City, Québec
G1V 0A6, Canada
e-mail: Frederic.Fontaine@chm.ulaval.ca
© Springer Nature Switzerland AG 2021
J. Chris Slootweg and A. R. Jupp (eds.), Frustrated Lewis Pairs,
Molecular Catalysis 2, https://doi.org/10.1007/978-3-030-58888-5_4
113
FLP-Mediated C–H-Activation
Yashar Soltani and Frédéric-Georges Fontaine
Abstract The C–H functionalization of aromatic molecules is a green approach
that allows creating complex molecules from simple reagents. While these transformations are mainly catalysed using transition metal complexes, the main group
molecules, including frustrated Lewis pairs, have been shown to be efficient species to
functionalize C–H bonds. This chapter describes the different approaches and mechanisms that are used to activate C–H bonds using Lewis acidic boron and silicon
species. On the one hand, highly electrophilic cationic boron and silicon species can
activate C–H bonds by an electrophilic addition pathway that generates a Wheland
intermediate that is further deprotonated by a Lewis base. On the other hand, frustrated Lewis pairs act in a concerted way where the Lewis acid activation and the
deprotonation by a base occur simultaneously. In both systems, the nature of the
Lewis acid and Lewis base plays an important role on the activity and the selectivity
of the functionalization reaction.
Keywords C–H activation · Electrophilic addition · Borylation · Silylation ·
Frustrated lewis pairs
Abbreviations
HBPin
4,4,5,5-Tetramethyl-1,3,2-dioxaborolane
HBCat Catecholborane
Pin
Pinacolate
Cat
Catecholate
9-BBN 9-Borabicyclo[3.3.1]nonane
3c-2e
Three-centre two-electron
AIBN
Azobisisobutyronitrile
Ar
ArylY. Soltani · F.-G. Fontaine (B)
Département de Chimie, Université Laval, 1045 Avenue de la Médecine, Québec City, Québec
G1V 0A6, Canada
e-mail: Frederic.Fontaine@chm.ulaval.ca
© Springer Nature Switzerland AG 2021
J. Chris Slootweg and A. R. Jupp (eds.), Frustrated Lewis Pairs,
Molecular Catalysis 2, https://doi.org/10.1007/978-3-030-58888-5_4
113