The 1-Silyl-1H-phosphirene/1,2-Dihydrophosphasilete Rearrangement and Its Preparative Significance

Abstract

Photolysis of the silyl-substituted 1H-phosphirene 3 a proceeds selectively with cleavage of a silicon ± silicon bond and ring expansion to furnish the 1,2-dihydro-1,2-phosphasilete 4 a. The corresponding heterocyclic germanium product, 4 b, is prepared analogously from 3 b. The preparative significance of 4 a is reflected not only in its numerous addition reactions to multiple-bond systems, such as alkynes 8 and 12 and ketene 10, but also in its substitution reactions with the chloro compounds 15, 18, and 21. The latter reactions proceed through the formation of chlorotrimethylsilane and the novel 1,2-dihydro-1,2-phosphasiletes (16, 19, and 22) which, depending on the substitution pattern at the phosphorus atom, undergo various isomerization reactions (16 317, 19 320). The hydrolysis of 4 a to 23 by mere traces of water in carefully purified tetrahydrofuran demonstrates the extreme sensitivity of this compound towards moisture.

Phosphorus Copies of PPV: π-Conjugated Polymers and Molecules Composed of Alternating Phenylene and Phosphaalkene Moieties

“…A summary of data collection and refinement parameters is listed in Table , and the bond lengths and angles for these and other phosphaalkenes pertinent to this discussion are summarized in Table . A survey of the Cambridge Crystallographic Database (CCD) for possible molecular models for the PPP s reported herein revealed 22 Becker-type phosphaalkenes. 40b,,− Of these, just seven feature carbon substituents on both the phosphorus and carbon atoms of the PC bond ( 12 , 13 , 14 , 15 , 16 ,40b 17 , and 18 57 ). To our knowledge, two other 1,4-arylene-bridged bis(phosphaalkene)s have previously been crystallographically characterized ( 18 57 and 19 ).…”

“…A survey of the Cambridge Crystallographic Database (CCD) for possible molecular models for the PPPs reported herein revealed 22 Becker-type phosphaalkenes. 40b,48,53-65 Of these, just seven feature carbon substituents on both the phosphorus and carbon atoms of the PdC bond (12, 48 13, 53 14, 54 15, 55 16, 40b 17, 56 and 18 57 ). To our knowledge, two other 1,4-arylene-bridged bis-(phosphaalkene)s have previously been crystallographically characterized (18 57 and 19 66 ).…”

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

“…Other [1,2]-rearrangements include α,β-epoxyphosphonate opening [47], β-halo-α-hydroxyphosphonate rearrangement [48], phosphirene rearrangement [49], or the unusual phosphonate-phosphinate rearrangement of dimethyl phosphonates [50]. Other [1,3]-rearrangements of organophosphorus compounds include phosphoenolpyruvate formation from phosphonopyruvate [51], benzylphosphonium salt formation from the corresponding o-methylaryl-substituted precursors [52], or the formation of ketophosphonates from vinylphosphates [53].…”

Valence isomerization of 2-phospha-4-silabicyclo[1.1.0]butane: a high-level ab initio study

“…Here, we report on the isomerization of 2-phospha-4-silabicyclo[1.1.0]butane A to its valence isomers 1-phospha-4-sila-1,3-butadiene B and 1,2-dihydro-1,2-phosphasilete C (only one other synthesis of 1,2-dihydro-1,2-phosphasiletes was reported: [ 26 – 28 ]), using high-level ab initio calculations at the (U)QCISD(T)/6-311+G**//(U)QCISD/6-31G* level of theory. We will compare the differences between a direct A → C pathway versus the isomerization via butadiene B .…”