10.1021/ja306947m.s004
Javier Carreras
Javier
Carreras
Mahendra Patil
Mahendra
Patil
Walter Thiel
Walter
Thiel
Manuel Alcarazo
Manuel
Alcarazo
Exploiting the π‑Acceptor Properties of Carbene-Stabilized Phosphorus Centered Trications [L<sub>3</sub>P] <sup>3+</sup>: Applications
in Pt(II) Catalysis
American Chemical Society
2012
nucleophilic attack
ligand
3P
phosphine 1
K 2PtCl
acceptor
Kinetic studies
polycyclic homo
DFT
substitution patterns
model transformation
2012-10-10 00:00:00
Dataset
https://acs.figshare.com/articles/dataset/Exploiting_the_Acceptor_Properties_of_Carbene_Stabilized_Phosphorus_Centered_Trications_L_sub_3_sub_P_sup_3_sup_Applications_in_Pt_II_Catalysis/2479078
Reaction of tris(dimethylaminocyclopropenium) substituted
phosphine <b>1</b> with K<sub>2</sub>PtCl<sub>4</sub> afforded
the bench stable
complex <b>3</b> which upon treatment with Ag[CB<sub>11</sub>H<sub>6</sub>Cl<sub>6</sub>] turned out to be an excellent catalyst
for the transformation of a variety of <i>ortho</i>-biaryl
substituted alkynes into polycyclic homo- and heteroarenes of different
size, shape, and curvature through a 6-<i>endo</i>-dig cyclization.
This constitutes the first example ever reported of using a P<sub>1</sub>-centered trication as ligand in catalysis. The strong π-acceptor
character of <b>1</b> that derives from its three positive charges
substantially increases the intrinsic π-acidity of Pt in complex <b>1</b>·PtCl<sub>2</sub> and dramatically enhances its ability
to activate π-systems toward nucleophilic attack. As a consequence,
a remarkable acceleration of the model transformation is observed
when compared with other classical π-acceptor ligands such as
P(OPh)<sub>3</sub> or P(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>. Moreover,
the employment of <b>1</b> as ligand also expands the scope
of this reaction to previously inaccessible substitution patterns.
Kinetic studies and deuterium labeling experiments as well as density
functional theory (DFT) calculations were performed in order to explain
these findings.