3‐Aryl‐λ ³ ‐phosphorine, 3‐Aryl‐λ ⁵ ‐phosphorine, 3‐Aryl‐λ ⁴ ‐phosphorinium‐Salze

Abstract

Die durch Reaktion von tert-Butyldi(1-propiny1)phosphan (3) mit (Brommethy1)ketonen 4 erhaltlichen 4-tert-Butyl-2-methy1-4-(1-propinyl)-6-R-4H-1,4-oxaphosphorin-4-ium-bromide 6 werden zu den 4-tert-Butyl-2-methy1-6-R-1,4-oxaphosphorin-4-oxiden 7 hydrolysiert, die durch saurekatalysierte Aldolkondensation in die I-tert-Butyl-I ,6-dihydro-5-R-3(2H)-phosphorinon-l-oxide 1 ubergefuhrt werden. Bei deren Umsetzung (R = Ar) mit Silicochloroform entstehen die 3-Aryl-ltert-butyl-l-chlor-h5-phosphorine 11, deren Konstitution durch Umwandlung in die 3-Aryl-1-tertbutyl-1-fluor(1-methoxy)-h5-phosphorine 12 bzw. 13 bewiesen wird. Die spektroskopischen Eigenschaften lassen die Annahme zu, daR das 1-tert-Butyl-1-chlor-3-phenyl-h5-phosphorin ( l l a ) in polaren Solventien im Gleichgewicht mit dem 1-terf-Butyl-3-phenyl-h4-phosphorinium-chlorid (18a) mit 4-bindigem Phosphor, K.Z.3, vorliegt. -Der Mechanismus der Bildung der 3-Aryl-ltert-butyl-1-chlor-1'-phosphorine 11 wird diskutiert. Er wird rnit der Umwandlung von l-tertButyl-l,2-dihydro-3-phenylphosphorin-l-oxid (14a) in 11 a mit Silicochloroform bewiesen. -Die Thermolyse der 3-Aryl-l-terf-butyl-l-chlor-h5-phosphorine 11 bei 250 -300 "C liefert die 3-Aryl-h3-phosphorine 2, die sich rnit Hg(OAc),/Methanol zu den 3-Aryl-1 ,1-dimethoxy-h5-phosphorinen 21 oxidieren lassen. -Die IR-, UV-, 'H-NMR-, l3C-NMR-und Massenspektren der einzelnen Verbindungsklassen werden diskutiert, die hochaufgelosten 'H-NMR-Spektren einiger h5-Phosphorine und der h3-Phosphorine werden nach LAOCOON-LAME bzw. DAVINS gerechnet. 3-Aryl-k3-phosphorins, 3-Aryl-l.s-phosphorins, 3-Aryl-k4-phosphorinium SaltsBy reaction of tert-butyldi(1-propyny1)phosphane (3) with (bromomethy1)ketones 4 the 4-tertbutyl-2-methyl-4-(1 -propynyl)-6-R-4H-oxaphosphorin-4-ium bromides 6 are obtained, which are degraded by hydrolysis to the 4-tert-butyl-2-methyl-6-R-1,4-oxaphosphorin 4-oxides 7. These oxides undergo an acid-catalyzed aldol-condensation to form the 1-tert-butyl-I ,6-dihydro-5-R-3(2H)-phosphorinone 1-oxides 1. Compounds 1 (R = Ar) react with silicochloroform to give the 3-aryl-l-tert-butyl-l-chloro-h5-phosphorins 11, the structure of which is proved by transformation into the 3-aryl-1 -fert-butyl-l-fluoro(1-methoxy)-h5-phosphorins 12 and 13, respectively. The spectroscopic properties indicate that in polar solvents 1-tert-butyl-1-chloro-3-phenyl-h5-phosphorin (Ha) forms an equilibrium with 1-tert-butyl-3-phenyl-h4-phosphorinium chloride (18a) with 4-bonding phosphorus, coordination number 3. -The mechanism of the formation of 3-aryl-l-tert-butyl-l-chloro-h5-phosphorins 11 is discussed. It is proved by the reaction of l-tertbutyl-I ,2-dihydro-3-phenylphosphorin 1-oxide (14a) with silicochloroform by which l l a is formed. -Thermolysis of the 3-aryl-l-tert-butyl-l-chloro-~5-phosphorins 11 at 250 -300°C affords the 3-aryl-h3-phosphorins 2, which form the 3-aryl-1 ,1-dimethoxy-h5-phosphorins 21 by oxidative alkoxylation with Hg(OAc),/methanol. -The IR, UV, 'H NMR, 13C NMR and, mass spectra of the various classes of compounds ...

One-step methylation of aromatic phosphorus heterocycles: synthesis and crystallographic characterization of a 1-methyl-phosphininium salt

“…4 Reactions of electrophiles at the phosphorus atom are therefore challenging and it is very difficult to access phosphininium ions directly, which are assumed to occur as intermediates in the formation of λ 5 -phosphinines. 5 Consequently, little is still known about phosphininium cations. Even though 2,4,6tris-t Bu-λ 3 -phosphinine can be protonated at the phosphorus atom with the in-situ generated, non-oxidizing superacid H[CHB 11 Me 5 Cl 6 ] to afford the 1H-phosphininium salt [H(C 5 H 2 t Bu 3 P)] + [CHB 11 Me 5 Cl 6 ] -(1-H, Chart 1), 1-phosphinines cannot be directly alkylated to 1Rphosphininium cations with classical reagents, such as alkyl halides or Meerwein salts.…”

Protodesilylation of 2,6-Disubstituted Silyphosphinines. Experimental and Theoretical Study

“…In most cases, these approaches rely on multistep procedures that are specific from the nature of the functional groups grafted at the 3 and 5 positions. [15][16][17][18][19][20][21][22][23] A few years ago we reported a synthetic strategy, which allows the synthesis of tetrafunctional derivatives. Polyfunctional compounds, [24][25][26][27] polydentate ligands, 28,29 and phosphorus macrocycles 30-33 could be easily prepared from disubstituted alkynes and 1,3,2-diazaphosphinine 1 through a cycloaddition/cycloreversion sequence which is depicted in Scheme 1.…”

“…Though many synthetic approaches toward functional phosphinines have been devised, most of these studies focused on the elaboration of 2,6-disubstituted derivatives and methods providing a convenient access toward 3,5-disubstituted compounds have been much less studied. In most cases, these approaches rely on multistep procedures that are specific from the nature of the functional groups grafted at the 3 and 5 positions. − A few years ago we reported a synthetic strategy, which allows the synthesis of tetrafunctional derivatives. Polyfunctional compounds, − polydentate ligands, , and phosphorus macrocycles − could be easily prepared from disubstituted alkynes and 1,3,2-diazaphosphinine 1 through a cycloaddition/cycloreversion sequence which is depicted in Scheme .…”