Reactions of phosphines with electron deficient boranes

Abstract

A series of classical B(C(6)F(5))(3)-phosphine adducts are shown to be reactive molecules. Reaction of (THF)B(C(6)F(5))(3) with phosphines are shown to effect ring-opening of THF affording the zwitterionic phosphonium-borate species of the form R(2)PH(C(4)H(8)O)B(C(6)F(5))(3) and R(3)P(C(4)H(8)O)B(C(6)F(5))(3). Alternatively, treatment of (THF)B(C(6)F(5))(3) with a lithium phosphide (R(2)PLi, R = tBu, Ph Mes) affords species of the form [Li(THF)(x)][R(2)P(C(4)H(8)O)B(C(6)F(5))(3)]. Additionally, double THF ring-opening is also demonstrated to give species of the form [Li(THF)(x)][R(2)P(C(4)H(8)OB(C(6)F(5))(3))(2)]. In addition a series of classical borane-phosphine adducts are also shown to undergo thermal rearrangement reactions to give the zwitterionic products of aromatic substitution R(2)PH(C(6)F(4))BF(C(6)F(5))(2) and R(3)P(C(6)F(4))BF(C(6)F(5))(2). The mechanism of these substitutions is considered. A series of crystallographic studies of phosphine-borane adducts, THF ring-opened zwitterions and para-attack zwitterionic phosphonium borates are reported and discussed.

Frustrated Lewis Pairs: Metal‐free Hydrogen Activation and More

“…[104] Analogous species are obtained with smaller phosphines after the combined toluene solutions of the reagents are heated under reflux. [105] …”

Frustrierte Lewis‐Paare: metallfreie Wasserstoffaktivierung und mehr

“…[104] Analoge Verbindungen werden auch von weniger sperrigen Phosphinen aus den Reagentien in Toluol bei Siedetemperatur erhalten. [105] …”

Dispersion‐Oriented Soft Interaction in a Frustrated Lewis Pair and the Entropic Encouragement Effect in its Formation

“…[19,31] FLPs can also participate in other reactions such as thermal rearrangement or ring-opening reactions. [32,33] Among these interesting behaviors, the heterolytic hydrogen splitting first observed by Stephan and co-workers [6] is of special interest as it can be adopted for the metal-free route for activating H 2 [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and subsequently reducing other functional groups, such as CN multiple bonds. [9][10][11][12][13] Furthermore, this metal-free splitting can potentially be developed into a new way of storing various gaseous molecules.…”