Asymmetric [2+2] Cycloaddition of (E)‐2‐(Diphenylphosphanyl)styrene Promoted by a Chiral Metal Template

Abstract

An organoplatinum complex containing the (S)-form of orthometalated [1-(dimethylamino)ethyl]naphthalene as the chiral auxiliary promotes the asymmetric [2+2] dimerization of (E)-2-(diphenylphosphanyl)styrene to generate two isomeric chelating diphosphanyl-substituted cyclobutane platinum template complexes in the ratio of 6:1. The four substituents on the cyclobutane rings adopt the pseudo-equatorial positions with an all-trans arrangement. The naphthylamine auxiliary can be removed chemoselectively from the template products by treatment with concentrated hydrochloric acid to form the corresponding dichloroplatinum(II) com-

A novel linkage-isomeric pair of dinuclear Pd(ii) complexes bearing a bis-bidentate tetraphos ligand

“…The cyclobutane carbon ring shows a folding angle of 152.4 • . Both ligand bite angles P(1)-Pd(1)-P(2) and P(3)-Pd(2)-P(4) of 94.52 (11) • and 94.35 (10) • , respectively, are significantly larger than that found for the more flexible mononuclear counterpart 1c of 90.09(4) • , while the Pd-P bond lengths are comparable in either complex: 2. 259(3), 2.254(3), 2.254(3) and 2.265(3) A (1a 6 •2.8DCE) vs. 2.250(1) A ˚(1c).…”

“…Both palladium atoms of the binuclear complex show a squareplanar coordination environment, built up by two cis coordinating chloride atoms and two phosphorus donor atoms attached to the 1,3 positions of the cyclobutane carbon ring, thus forming two six-membered metallarings almost perpendicular to each other with a dihedral angle of 86.34 (11) • . Accordingly, the related mononuclear bis-phosphonium modified complex [PdCl 2 (o-MeO-PCP)](PF 6 ) 2 exhibits a comparable dihedral angle of 86.43 (10) • . 2b…”

“…CCDC reference numbers 694966 and 694967. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/b815392b the Pd II centre has been suggested to occur in the course of copolymerization reactions, influencing the kinetics of the overall catalytic process. 4 The reaction conditions for CO-olefin copolymerization can significantly influence the performance of Pd II -diphosphane precursors, as shown by a comparison of the catalytic productivity (kg (polyketone) …”

Syntheses of Bimetallic Zwitterionic Complexes Containing Stereogenic Bifunctionalized Phosphine through Stepwise Insertion and Hydration Reactions

“…For example, the palladium or platinum complexes containing 1-(dimethylamino)ethylnaphthalene as auxiliary promoted the Diels−Alder reaction between dialkenylphenylphosphine with DMPP (3,4-dimethyl-1-phenylphosphole) to incorporate one of the alkene moieties into the bicyclo[2.2.1] group, thus generating a stereogenic center at phosphorus . In our group's previous works, palladium and platinum complexes promoted [4+2] ,, and [2+2] cycloaddition, hydrophosphination, hydroarsination, and hydroamination have been developed for the asymmetrical synthesis of chiral phosphines. Among these reactions, the above strategy, viz., functionalization of one unsaturated carbon−carbon bond of dialkenylphenylphosphines or dialkynylphenylphosphines, was often utilized in order to generate a stereogenic phosphorus.…”

Application of metallacycles toward asymmetric cycloaddition and hydrophosphination reactions

“…Our group had also proved that the platinum (II) template could promote asymmetric [2+2] cycloaddition reaction. 47 The stereoselectivity is very good, up to 6:1. Since the two cycloaddition products could not be separated by silica-gel column chromatograghy, the mixture of the two cycloadducts were treated with concentrated hydrochloric acid to remove the naphtlylamine auxiliary and generate the corresponding dichloro complexes.…”