Planar-to-Axial Chirality Relay in Phospharuthenocenes. A Rotationally Hindered 2-(2‘-Diphenylphosphinonaphth-1‘-yl)phospharuthenocene

Abstract

Competing steric pressures within the coordination sphere of 2-(2‘-X-naphth-1‘-yl)-3,4-dimethyl-5-phenyl-η5-phospholyl(pentamethylcyclopentadienyl)ruthenium(II) complexes (X = OMe (1), OH (3), OTf (4), PPh2(O) (5), PPh2 (6)) give rise to a well-defined and predictable axial chirality about the phospharuthenocene−naphthyl bond. Crystal structure analysis of the platinum complex cis-[Pt(6)Cl2] (7) shows a very different geometry from that found in cis-[Pt(1)(PEt3)Cl2] (2) because of the leverage exerted on the Pt coordination sphere by the (2‘-PPh2-naphth-1‘-yl) functionality.

Double Friedel–Crafts Acylation Reactions on the Same Ring of a Metallocene: Synthesis of a 2,5‐Diacetylphospharuthenocene

“…The crystal‐structure studies (Table 1, Scheme ) of the non‐, mono‐, and diacylated phospharuthenocenes gave clean, accurate data for 29 and 30 but some rotational disorder of the phospholyl ring was found in the non‐substituted complex 22 ; its PC and C α C β lengths are presented as averaged values in Scheme and these appear reasonable when compared with other related phospharuthenocenes that are substituted by weakly conjugating groups 39. 40, 42, 43 The structure of the previously described40 complex 24 was also determined for completeness.…”

“…[39,40,42,43] The structure of the previously described [40] complex 24 was also determined for completeness.…”

Transition-Metal-Catalyzed C-P Cross-Coupling Reactions

“…A phospharuthenocene-based ligand was also prepared by a similar procedure (not shown). 115 Compared to the palladium-catalyzed cross-couplings of secondary phosphine oxides, the nickel-catalyzed reactions are rarely used. The latter were mainly applied to the introduction of a second phosphorus substituent in ortho,ortho¢ binaphthyls after reduction of the former synthesized monophosphine oxide.…”

Synthesis and Evaluation of Side-Arm-Alkylated Phosphametallocene Phosphines

“…However, recent crystallographic evidence has shown quite clearly that the rather nondirectional nature of the sp 2 donor allows the conformational needs of the side arm to be expressed quite strongly. For example, the very different localization of the platinum atoms in complexes 5 and 6 , (Figure ) reflects leverage from the naphthyl group and demonstrates the responsiveness of the phosphametallocene element to the sterical preferences of the sp 3 phosphorus atom. , …”

“…Thus it seemed likely that elaborating the side arm of the phosphametallocen-2-ylmethylphosphines should also set up conformational relays that might modify ligand properties and performance quite profoundly. Well-developed functionalization chemistry of this kind is available only for rac- phosphaferrocenes, a class that includes an analogue of compound 2 described here; the generation of enantiopure phosphametallocenes, − ,,− or those based upon late transition metals other than iron, − ,,− is still in its infancy. The study presented here shows that resolved ligands having side-arm C-functionalization are quite easily accessed from the readily available enantiopure phospharuthenocene source 7 , through syntheses that exploit the extreme stability ,,, of the previously unknown mono- and dimethyl-substituted phospharuthenocenemethylium ions.…”