A novel series of π-complexes of phosphino ligands, [Cp*Ru(η6-arene-PAr2)][OTf], has been prepared in which the diarylphosphine unit is attached to a metalated π-arene scaffold. These organometallic phosphino ligands display either an electron-donating methyl group (−PAr2 = −P(p-tol)2) or electron-withdrawing trifluoromethyl group (−PAr2 = −P(p-C6H4CF3)2). This unique class of metallo ligands was converted
A new family of cyclometalated (N-heterocyclic carbene)-PtII complexes bearing monodentate phosphines as ancillary ligands has been designed for use as precatalysts in 1,6-enyne cycloisomerization reactions. Highly enantioselective skeletal rearrangements of allylpropargyl-tosylamide derivatives have been developed by using (S)-Ph-Binepine as the chiral auxiliary. Enantiomeric excesses up to 97% have
Platinum-Catalyzed Cycloisomerization Reactions of Enynes
作者:Alois Fürstner、Frank Stelzer、Hauke Szillat
DOI:10.1021/ja0109343
日期:2001.12.1
PtCl(2) constitutes an efficient and practical catalyst for a set of different atom economical rearrangement reactions of enynes. This includes (i) a formal enyne metathesis reaction delivering 1,3-dienes, (ii) the formation of polycyclic vinylcyclopropane derivatives, and (iii) an unprecedented O-->C allyl shift reaction if unsaturated ethers are employed. Although these transformations produce significantly
Gold(I) complexes bearing monophosphole ligands were synthesized, and their electronic and steric properties were compared to those of their triphenylphosphine-based counterparts. Cationic phosphole-based gold(I) complexes are active and selective in enyne cycloisomerization and in olefin cyclopropanation, with a good correlation between the ligand σ-donor ability and the catalytic activity. For the
used in enyne cycloisomerisations in order to study the effect of the ligand on the catalytic activity and selectivity. Reactions were performed on various N- or C-tethered 1,6-enynes and in the absence or in the presence of nucleophiles. For the most efficient cationic Pt(II)-complexes, it was also evidenced that the counterion and/or the solvent could have an influence on both the efficiency and the