trans-5-Palladatricyclo[4.1.0.02,4]heptanes: Complexes with monodentate, weakly coordinating ligands, formation of new derivatives and synthetic limitations

Abstract

The bis(acetone) complex of tetramethyl rac‐3,3,7,7‐tetramethyl‐trans‐5‐palladatricyclo[4.1.0.02,4]heptane‐1,2,4,6‐tetracarboxylate rac‐1a was crystallized and investigated by X‐ray structure analysis. Unlike in complexes with bidendate ligands in rac‐1a · 2(acetone), only a small deviation from the square planar coordination of palladium was observed. Efforts to crystallize the analogous pyridine, acetonitrile and benzonitrile complexes failed; but the labile complexes rac‐1a · 2([D5]pyridine) and rac‐1a · 2([D3] acetonitrile) as well as rac‐1a · 2([D6]acetone) could be characterized by 1H and 13C NMR spectra and a fast ligand exchange was proven by nmr. Then the ability of different 1,2‐disubstituted cyclopropenes to form trans‐5‐pallada‐tricyclo[4.1.0.02,4] heptanes 1 was investigated. Only the diesters 5c–e lead to PTHs, with a diester possessing sterically demanding substituents in 3‐position of the cyclopropene and with other substituents in 1‐ respectively 2‐position of the cyclopropene either the cyclopropene‐formation or the PTH‐formation failed.

Tetraallyl (2,2′-bipyridyl)-rac-3,3,7,7-tetramethyl-trans-5-palladatricyclo[4.1.0.02,4]heptane-1,2,4,6-tetracarboxylate above and below the phase-transition temperature of 194 K

“…Intramolecular CÐHÁ Á ÁO interactions very similar to those in the title compound have been observed in the crystal structures of related palladatricyclo[4.1.0.0 2,4 ]heptanes Hashmi, Naumann & Bolte, 1998;. Thus, these interactions appear characteristic for this group.…”

Bioconjugates of Enantiomerically Pure Organopalladium Compounds by Metal‐Assisted Positional Selective Transesterifications at Palladium Enolates

“…The Pd À C lengths are 2.034(3) and 2.044(3) . Both PdÀN lengths are 2.088 (3) . The Pd atom only shows a small deviation from planarity; the angle between the plane through N1, Pd, and N2 and the plane through C1, Pd, and C4 is 4.38.…”

“…The angle between the C1-Pd-C4 plane and the N1-Pd-N2 plane is 14.88. This deviation from One further crystal structure analysis was obtained for the bis-acetone complex [3] of bis-oestradiol ester 5 g (Figure 6). [10,25] It again confirms that the two ester groups next to palladium are selectively exchanged in the course of the acid-catalyzed transesterification.…”

“…[1] on derivatives of type 1, which require stabilization by strongly coordinating ligands, and the work of Maitlis et al [2] on palladoles 2, which are resistant to oxygen and heat without such stabilizing ligands, we reported the synthesis, [3] resolution, [4] stereoselective synthesis, [5] and stoichiometric [6] and catalytic [7] chemistry of palladacycles of type 4.…”

Bis{μ-dimethyl 1-[1-methoxycarbonyl-3-(methoxyoxalyl)-2-methylpropenyl]-3,3-dimethylcyclopropane-1,2-dicarboxylato(2–)}bis[(triphenylphosphine)palladium(II)] acetone solvate

“…Comment 5-Pallada-anti-tricyclo[4.1.0.0 2,4 ]heptanes are an interesting class of chiral organopalladium compounds which are usually stable in water and air (Hashmi, 2002). Several complexes of these compounds have been prepared (Hashmi, Naumann, Probst et al, 1997;Hashmi, Naumann, Bolte & Rivas Nass, 1998;Hashmi, Bats et al, 1998) and their reactivity has been studied (Hashmi et al, 1999). We have now tried to prepare the complex with the simple triphenylphosphine ligand, which immediately led to a precipitate with low solubility.…”