Chirale Tripod‐Liganden mit Phosphit‐Donorgruppe: Synthese und Komplexchemie

Abstract

Chiral Tripodal Ligands Bearing a Phosphite Donor Group: Synthesis and Coordination Chemistry The mechanism of the reaction of epichlorohydrine (H–CH2Cl) (1) with lithium phosphides is analysed. A neighbouring‐group mechanism has been found to be the essential driving force in this reaction. Monophosphanyl alcohols such as HOCH(CH2P(Ph)2)(CH2Cl) (2) and epoxides (Ph)2PCH2– (3) are characterized as intermediates. The mechanism leads to a rapid one‐pot method for the synthesis of chiral racemic as well as enantiomerically pure bis(phosphanyl) alcohols HOCH(CH2PR2)(CH2PR 2′) (4). The resulting bis(phosphanyl) alcohols 4 react easily with X2PCl (X = Cl; Ph; or X2 = 1,2‐ethanedioxy‐2,2′‐biphenyldiyldioxy‐) to yield the mixed donor group tripodal ligands X2POCH(CH2PR2)(CH2PR′2) (5, 6) containing both phosphite, phosphinite or phosphorodichloridite and phosphane donor groups. The identity of these compounds were proved by 1H‐, 31P‐ and 13C‐NMR spectroscopy, mass spectra, microanalysis as well as X‐ray analysis. The coordination capabilities of these novel ligands are demonstrated by the synthesis and characterization of a (cyclooctadiene)rhodium complex {[(5c)Rh(I)COD]PF6} (7) of the ligand 5c, exhibiting the typical hetero‐bicyclooctane tripod metal cage of this type of tripod complexes.

Multidentate Phosphinoalkoxides: Synthesis, Deprotonation, and Building Blocks in Polylithium Mixed-Anion Aggregates

“…Despite their conceptual simplicity, the multidentate phosphino alcohols I and II have not been explored in depth. 3c, Recent studies were mainly concerned with synthesis and transition metal complexes of a few perphenylated examples of I and II . To the best of our knowledge, the permethylated phosphino alcohols I and II (R = Me) have not been described previously at all.…”

Phosphorus containing mixed anhydrides—their preparation, labile behaviour and potential routes to their stabilisation

“…Next, the effects of electron withdrawing atoms (approach A) were explored by constructing series II. Following a literature based procedure, 13,14 chlorophosphites 4 and 5 were reacted with a suspension of sodium propanoate in thf at 45 °C for 2 h to afford ( propanoyl)phosphites 8 and 9, respectively, upon workup (Scheme 3). Overall, 8 and 9 displayed much greater stability than the (acyloxy)phosphines and no rearrangement products of the general formula (RO) 2 P(O)P(OR) 2 were observed for these compounds.…”

“…These compounds were prepared according to a modified literature procedure. 14 A solution of the appropriate diol (9.22 mmol) in thf (20 ml) was added to a solution of PCl 3 (1.27 g, 9.22 mmol, 0.81 ml) in thf (10 ml) at −40 °C. NEt 3 (1.87g, 18.45 mmol, 2.57 ml) was then added dropwise via a syringe to the colourless solution.…”

Thiolate and Thioether Functions as Donor Groups X, Y in Tripod Ligands RCH2C(CH2PPh2)(CH2X)(CH2Y) – Synthesis and Coordination Chemistry

“…One argument in favor of the η 3 coordination of the ligand in 6a comes from a comparison of the 13 C-NMR resonances observed for compounds which definitely contain the ligands in η 2 coordination (e.g. 5) and a series of examples in ref.…”

“…A still broader scope of this chemistry could be envisaged if it were possible to synthesize ligands CH 3 C(CH 2 X)(CH 2 Y)(CH 2 Z) with up to three different phosphorus donor groups. The 1 R R Ј 2 R R Ј difficulties characterizing the neopentane chemistry, which is at the basis of such syntheses, had only recently been 1a [5] [6] [7] [8] [9] [10] [11] [12] [13] with even enantioselective syntheses of such ligands having been reported [10] . The introduction of sulfur and nitrogen donors instead of phosThis second method was used to transform compounds 1 [18] [19] , containing at least one SBzl group into tripod liphorus donor functions in this type of tripod ligand has by now not yet found a general solution.…”