“Low-coordinate” 1,2-oxaphosphetanes – a new opportunity in coordination and main group chemistry

Abstract

While 1,2σ5λ5-oxaphosphetanes are well known intermediates from the Wittig-reaction, no 1,2σ3λ3-oxaphosphetanes have been described, so far. Herein, we present the first synthesis of 1,2σ3λ3-oxaphosphetanes derived from their κP-Mo(CO)5 complexes and first investigations towards metal coordination and P-oxidation. Bonding, ring strain energy and potential retro-[2+2] cycloaddition reactions of the 1,2-oxaphosphetane ring were studied by DFT methods.

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

“…Investigations regarding the release of the free phosphane ligands from iron centers in 3 – 5 and 6 were not conducted so far. Nonetheless, we are confident that decomplexation could be achieved upon reaction with dppe under appropriate conditions, like it was shown recently for a 1,2‐oxaphosphetane molybdenum complex (see introduction) …”

“…In doing so, we were able to build up a versatile collection of secondary aminophosphanes while being coordinated to a transition metal fragment . The extraordinary potential of this methodology was increased due to the recently demonstrated option to cleave the metal‐phosphorus bond in case of 1,2‐oxaphosphetane complexes and, hence, enabling access to the free, strained P‐ligand . Therefore, we saw a chance to re‐open the research field on II and maybe III , by applying the same strategy to the synthesis of V and VI .…”

Quantum Chemical Calculations on CHOP Derivatives—Spanning the Chemical Space of Phosphinidenes, Phosphaketenes, Oxaphosphirenes, and COP− Isomers

“…Also, properties derived from the topological analysis of the electron density, in line with Bader’s AIM (atoms-in-molecules) theory [43,44,45], in particular the electron density itself (ρ) and the Lagrangian kinetic energy ( G ) computed at the bond critical point (BCP), were calculated. The latter was only recently used in characterizing bond strength in phosphorus-containing three-membered heterocycles [46] and, soon afterwards, the Lagrangian kinetic energy density per electron ( G /ρ) was reported as a remarkable bond-strength property [47] which correlates with ring strain energies (within a series) when computed at the ring critical points [48].…”

“…As double bonds normally entail enlarged bond angles, their incorporation into small cyclic systems should be expected to result in an increase in the RSE, as occurs, for instance, in moving from cyclopropane to cyclopropene (RSE = 29.0 and 54.5 kcal/mol, respectively [52]). In the case of the parent oxaphosphirene ring system 1a , the RSE was computed by evaluating the energetics of appropriate homodesmotic reactions (Scheme 5), similar to those used for other three- [46,48,51,53,54,55,56,57] or four-membered [47] saturated phosphorus heterocycles. In such reactions, for the cleavage of every endocyclic X–Y (or X=Y) bond, a H n X–YH m (or H n X=YH m ) reagent is used, the valences of X and Y being completed with H atoms.…”

Theoretical Study of The Reaction of Ketene with Methanimine Using DFT Method

“…The small heterocycles with two heteroatoms, e.g. oxaphosphetanes and thioanalogues prepared from Witting reaction intermediate, also attract researchers due to their reactivity (Espinosa Ferao & Streubel, 2020;A. Kyri et al, 2018;A.…”