Epoxide-like Chemistry: 1,2-Bifunctional P-Ligands via Stereo- and Regioselective Ring Opening of an Oxaphosphirane Complex

Abstract

Facile stereo-and regioselective ring opening of the oxaphosphirane complex A is presented using small molecules with differently polar E−H bonds (HCl, H 2 O, and NH 3 ). The synthetic potential of the thus obtained novel 1,2-bifunctional ligands B is illustrated in cyclocondensation reactions, leading to the novel heterocyclic Pligands C.

Access to 1,1′‐Bifunctional Phosphane Iron(0) Complexes via P–N Bond‐Forming Reactions and Selective P‐Functionalizations

“…This role can be effected by solvent (or basic reagent) molecules that, for the current study, were modelled by explicit NH 3 units. The most favourable situation was found for the use of four explicit NH 3 molecules, similar to the reported “chain of water molecules” used to explain a hydrolysis reaction in oxaphosphirane complexes . This initially forms a multicomponent van der Waals complex 2′ an · 4NH 3 (Scheme ) favouring nucleophilic displacement of chloride anion to yield intermediate 8′· Cl – · 3NH 3 and allowing an effective proton transfer chain from the ammonia ligand in 8′ to the P atom in aminophosphane 3′· Cl – · 3NH 3 through the aminophosphanide complex 9′· Cl – · NH 4 + · 2NH 3 as intermediate (Scheme ).…”

Terminal Phosphinidene Complex Adducts with Neutral and Anionic O-Donors and Halides and the Search for a Differentiating Bonding Descriptor

“…Herein, a comprehensive study on the electrophilic terminal phosphinidene pentacarbonyltungsten(0) complex adducts with halides ( 1a – d ), as well as with the very important family of O-donor ligands ( 1e – 1q ), is presented (Figure ) using model P-methyl-substituted derivatives for the sake of computational efficiency. It should be noted that halide adducts constitute the phosphanido part in e.g., solvent-separated Li/Cl phosphinidenoid complexes, which have gained increasing synthetic importance as low-temperature synthetic equivalents of phosphinidene complexes. ,,, In the case of an ambident nitric oxide (NO) ligand, it is considered to be both an O donor ( 1p ) and a N donor ( 1r ). The latter adduct 1r still bears an available terminal O atom capable of acting as a donor ( 1q ), and the same holds for 1p being able to act as a N donor ( 1s ).…”

Between Oxirane and Phosphirane: The Spring‐loaded Oxaphosphirane Ring

“…In order to show the extrapolation of this effect into oxaphosphirane chemistry, the C−O cleavage ring‐opening reaction by nucleophilic attack of a single molecule of methanol as a model reagent was studied for the parent oxaphosphirane ( 1 a1 ) and its pentacarbonyl−tungsten(0) κ ‐ P ‐complex ( 1 a5 ). The hydrolysis mechanism for a model oxaphosphirane k ‐P−W(CO) 5 complex with up to five explicit water molecules was previously reported [41] …”

“…The hydrolysis mechanism for a model oxaphosphirane k-PÀ W(CO) 5 complex with up to five explicit water molecules was previously reported. [41] First of all, initial van der Waals complexes are formed in both cases, either through hydrogen bonds or O•••P pnictogen bonds [42] (1 a1•MeOH P and 1 a5•MeOH P ), the latter profiting from a Lewis pair interaction of the lone pair at the O with the P atom σ-hole [43] (Figure 4) with bonding distance of 2.784 and 2.906 Å, respectively. As previously noticed for the case of 3imino-azaphosphiridine complexes, [44] this preliminary pnictogen bond formation entails a small yet significant enhancement of ring strain, as deduced from the increase of G(r)/1(r) at RCP (vide supra) for both 1 a1•MeOH P (1.1815 au) and 1 a5•MeOH P (1.2068 au) compared to the respective non-interacting species (1.1574 and 1.1423 au, respectively).…”