210
T. A. Gazis et al.
MeOH
Methanol
Mes
Mesityl
NBS
N-bromosuccinimide
Ph
Phenyl
PhH
Benzene
PhMe 2 SiH Phenyl dimethylsilane
THF
Tetrahydrofuran
TMEDA
Tetramethylethylenediamine
Ts
Tosyl
6.1 Introduction
The seminal work in the field of frustrated Lewis pair (FLP) chemistry was reported
by Stephan in 2006, where it was observed that a borane-based strong Lewis acid
and a phosphine-derived Lewis base did not form the corresponding classical Lewis
adduct. This work detailed the synthesis of a rigid tetrafluorophenylene-bridged phosphoniumfluoroborate, which was subsequently transformed into the corresponding
borohydride (Fig. 6.1a) [1]. Upon heating of the zwitterionic species, molecular
hydrogen (H 2 ) was liberated, generating a phosphinoborane. The highly rigid linker
and the steric bulk of the substituents on the phosphorus and boron moiety precluded
the formation of the classical Lewis adduct. Very soon after Stephan’s seminal report,
Fig. 6.1 Seminal reports of FLPs reported by Stephan and Erker
T. A. Gazis et al.
MeOH
Methanol
Mes
Mesityl
NBS
N-bromosuccinimide
Ph
Phenyl
PhH
Benzene
PhMe 2 SiH Phenyl dimethylsilane
THF
Tetrahydrofuran
TMEDA
Tetramethylethylenediamine
Ts
Tosyl
6.1 Introduction
The seminal work in the field of frustrated Lewis pair (FLP) chemistry was reported
by Stephan in 2006, where it was observed that a borane-based strong Lewis acid
and a phosphine-derived Lewis base did not form the corresponding classical Lewis
adduct. This work detailed the synthesis of a rigid tetrafluorophenylene-bridged phosphoniumfluoroborate, which was subsequently transformed into the corresponding
borohydride (Fig. 6.1a) [1]. Upon heating of the zwitterionic species, molecular
hydrogen (H 2 ) was liberated, generating a phosphinoborane. The highly rigid linker
and the steric bulk of the substituents on the phosphorus and boron moiety precluded
the formation of the classical Lewis adduct. Very soon after Stephan’s seminal report,
Fig. 6.1 Seminal reports of FLPs reported by Stephan and Erker