The Reaction of Terminal Phosphinidene Complexes With Electron-Rich Alkynes: A New Approach to the Phosphole Ring

Abstract

The reaction of electron-rich alkynes such as ethoxyacetylene or propynyldiethylamine with a transient terminal phosphinidene complex such as [PhP=W(CO),] directly yields the corresponding phosphole complexes via a formal [2 + 2 + I ] cycloaddition involving two molecules of alkyne and one phosphorus center.

Synthesis and Structure of Metal Complexes of P-Stereogenic Chiral Phosphiranes: An EDA-NOCV Analysis of the Donor–Acceptor Properties of Phosphirane Ligands

“…Higham and co-workers suggested that the observations for rhodium complexes could be explained if the PCH 2 CH 2 group in phosphiranes, because of the pyramidalized structure and increased s-character of the donor orbitals, was a poorer σ-donor than PMe 2 . , A similar rationalization is plausible for the Mo complexes. In contrast, no difference in the CO stretching frequencies for W­(CO) 5 complexes was observed. , However, this system is particularly insensitive to phosphine structure, so that electronic differences among PPh 3 , PMe 3 , and the mixed arylmethylphosphines PPh 3– n Me n ( n = 0–3) could not be determined by vibrational spectroscopy …”

“…A solution of syn-1 (40 mg, 0.11 mmol, 1 equiv per Pd) in CH 2 Cl 2 (2 mL) was added to a yellow solution of [Pd(C 3 H 5 )Cl] 2 (20 mg, 0.053 mmol, 0.5 equiv of complex, 1 equiv of Pd) in CH 2 Cl 2 (2 mL); the mixture immediately turned lighter yellow. The solvent was removed, and the product was recrystallized from pentane, yielding a yellow solid (35 trans-Rh(syn-(R P ,S C )-Mes*PCH 2 CHPh) 2 (CO)(Cl) (8). A solution of syn-1 (20 mg, 0.051 mmol, 2.0 equiv per Rh) in CH 2 Cl 2 (0.5 mL) was added to a solution of [Rh(CO) 2 Cl] 2 (5 mg, 0.013 mmol, 1.0 equiv) in THF (0.5 mL).…”

“…In contrast, no difference in the CO stretching frequencies for W(CO) 5 complexes was observed. 35,36 However, this system is particularly insensitive to phosphine structure, so that electronic differences among PPh 3 , PMe 3 , and the mixed arylmethylphosphines PPh 3−n Me n (n = 0−3) could not be determined by vibrational spectroscopy. 37 For comparison, we computed the structures and IR spectra of phenylphosphirane and phenyldimethylphosphine complexes in these Rh, Mo, and W systems, as well as for Ni(CO) 3 L, using two different density functionals (Table 4).…”

“…Ar CH), 124.26 (Ar CH), 121.7 (d, J = 33, quat Ar), 116.3 (br m, allyl CH), 75.2 (overlapping d, J = 37, allyl CH 2 ), 62.9 (allyl CH 2 ), 62.6 (allyl CH 2 ), 40.4 (quat t-Bu), 40.3 (quat t-Bu), 40.2 (quat t-Bu), 40.0 (quat t-Bu), 35.2 (br, 2 ortho t-Bu CH 3 ),35.1 (ortho t-Bu CH 3 ),35.0 (ortho t-Bu CH 3 ), 34.8 (quat t-Bu), 34.5 (quat t-Bu), 33.1 (d, J = 20, CH), 32.8 (d, J = 29, CH), 31.2 (overlapping, 2 para t-Bu CH 3 ), 22.9 (d, J = 18, CH 2 ), 22.8 (d, J = 15, CH 2 ). The para t-Bu signals for the two diastereomers appeared to overlap in the 1 H NMR and the13 C{ 1 H} NMR spectra, and one ortho t-Bu CH 3 peak was not observed; it is likely overlapping with another signal.…”

Probing the Structural and Electronic Effects on the Origin of π-Facial Stereoselectivity in 1-Methylphosphole 1-Oxide Cycloadditions and Cyclodimerization

“…The Diels–Alder reactions of P­(IV) derivatives of phosphole have attracted the attention of experimental and computational chemists because such reactions form a 7-phosphanorbornene moiety that holds unique properties of its P-center. − The significance of the 7-phosphanorbornene derivatives was explained by Quin, Mathey et al, in fragmentation-related phosphorylation reactions, , complexations, − and in refunctionalization − including deoxygenations. − Westheimer first reported the preparation of P­(IV) derivatives of phosphole, which was further explored for the synthesis of the dimers of phosphole derivatives including oxides, sulfides, and quaternary salts. − …”