Phosphasilene synthesis and reactivity: an improved route to 1-(2,4,6-tri-tert-butylphenyl)-2-tert-butyl-2- (2,4,6-tri-isopropylphenyl)phosphasilene

Advances in Phosphasilene Chemistry

“…Arylphosphasilenes 8 a and P ‐silyl derivative 3 exhibit weak absorptions, assigned as π–π* and n–π transitions. Indacenyl‐substituted phosphasilenes 9 a , possessing highly coplanar frameworks with perpendicularly‐fixed Rind groups, exhibit intense bathochromically shifted absorption bands (Table ).…”

“…More thermally stable phosphasilenes at high temperatures often afford the products of intramolecular cyclization reactions of the Si=P bond with the organic substituents at phosphorus or silicon atoms. The phosphasilene Tip( t Bu)Si=PMes*, for example, eliminates isobutylene and affords the formal Ar−H addition product (Ar is a former Mes* group) . Thermolysis of phosphasilene Tip 2 Si=PSi i Pr 3 ( 3 ) at T >110 °C proceeds differently, resulting in formation of the cyclic product due to the C−H bond activation .…”

“…Phosphasilenes readily react with protic reagents in a 1,2‐addition manner (Scheme ) . Natural polarization of the δ+ Si=P δ− bond favors protonation of negatively polarized phosphorus and addition of anions to the electrophilic silicon atom.…”

Chalcogenation reactions of a stable ferrocenyldiphosphene: Formation of thia‐, selena‐, and telluradiphosphiranes

“…The benzene-d 6 solution of 4a showed an AB quartet signal with 1 J PP = 204 Hz at −89.6 and −70.6 ppm in the 31 P NMR spectrum, which are characteristic values of a three-membered framework for chalcogenadiphosphiranes as summarized in Tables 1-3. The former resonance (−89.6 ppm) had satellite signals of 1 J TeP = 100 Hz due to 125 Te isotope with 7% natural abundance, whereas the latter satellite signals (−70.6 ppm) exhibited 1 J TeP of 260 Hz, which is similar to those of three-membered heterocycles containing phosphorus and tellurium atoms, that is, 229 Hz for t-BuP(Te)P(t-Bu) (4g) [31,32] and 222 Hz for Ar 2 Si(Te)PMes * (Ar = 2,4,6-Et 3 C 6 H 2 ) [34]. The observed difference of the coupling constants for 4a can be interpreted in terms of hybridization of the phosphorus atoms.…”

2,4,6‐Tri‐tert‐butylphenyl and 2,4‐di‐tert‐butyl‐6‐methylphenyl groups: Look similar, react differently

“…Instead, lithium trimethylsilyl(2,4,6-tri-tert-butylphenyl)phosphide behaved as a highly efficient base toward the weak acidic protons of the acetonitrile and lithiated it. The indication that lithium trimethylsilyl(2,4,6-tri-tertbutylphenyl)phosphide can be an efficient base has been discussed in reports of the synthesis of phosphasilenes [13,14]. The in situ formed lithium methylene nitrile 5 added to the carbonyl group of 4.…”