Heteroatom Chemistry

Quin, Louis D.; Wu, Xiao‐Ping

doi: 10.1002/hc.520020303pmid: N/A

Oxidation of 3,4‐dimethyl‐1‐phenylphosphole with peracids or peroxides gives a relatively stable P‐oxide, which can be used in Diels‐Alder reactions to give derivatives with the 7‐phosphanorbornene framework. Oxygen insertion into a C–P bond of this framework occurs smoothly with m‐ chloroperbenzoic acid (MCPBA) providing derivatives of the 2,3‐oxaphosphabicyclo [2.2.2] octene ring system. The phosphole can be converted to this system in a one‐pot synthesis by reaction with excess MCPBA in the presence of N‐phenylmaleimide as dienophile. The phosphole oxide undergoes mono‐epoxidation with MCPBA. Thermal or photochemical fragmentation of the 2,3‐oxaphosphabicyclo [2.2.2] ocetene is a useful source of the 3‐coordinate species Ph–PO2, a meta‐anhydride of phenylphosphonic acid. This species was trapped successfully with a variety of alcohols.

Litvinov, Igor A.; Karaghiosoff, Konstantin; Schmidpeter, Alfred; Zabotina, Elena Y.; Dianova, Evelina N.

doi: 10.1002/hc.520020304pmid: N/A

Condensation of 2‐aminopyridine and chloromethyldichlorophosphane yields 1,3,4‐diazaphospholo[1,2‐a]pyridine 2. Methanol adds to 2 while diethylamine does not; with additional elemental sulfur, in both cases the sulfides 4, 6 of the respective adducts are formed. Hydrolysis of 2 specifically opens the PN‐bond and gives the zwitterionic 2‐aminopyridinio‐methylphosphonite 7. The compound crystallizes with one molecule water in the monoclinic space group P21/c with a = 25.490(7)Å, b = 7.365(4)Å, c = 9.088(3)Å, β = 100.06(3)°, and Z = 8 with two independent molecules of 7 and of water. In the crystal hydrogen bonds connect the molecules of 7 to form double‐chain structured polymers. The individual double‐chains are linked to each other by hydrogen‐bonded water molecules.

Deschamps, Eliane; Ricard, Louis; Mathey, François

doi: 10.1002/hc.520020305pmid: N/A

Further studies have been conducted on the condensation of electron‐rich arenes or heteroarenes with the dienic system of phosphole P‐complexes. According to the X‐ray crystal structure analysis of one of the resulting 2‐aryl‐3‐phospholene P‐complexes, the condensation takes place on the side of the diene opposite to the complexing group. The decomplexation of the phospholene P–Mo(CO)5 and P–W(CO)5 complexes, respectively, by reaction with sulfur or halogens and tertiary amines yields the corresponding P‐sulfides and oxides with full retention of the stereochemistry at phosphorus. Double condensation of the phosphole P‐complexes onto the 2 and 5 positions of thiophene and furan ultimately leads to phosphole–thiophene–phosphole and phosphole–furan–phosphole chains. The first type has been characterized by X‐ray crystal structure analysis of its P,P‐disulfide. No electronic delocalization appears to take place along the chain.

Grobe, Joseph; Van, Duc Le; Althoff, Ulrike; Krebs, Bernt; Dartmann, Mechtild; Gleiter, Rolf

doi: 10.1002/hc.520020306pmid: N/A

The one‐pot reaction of the alcohol adducts F3CP(H)CF2OR of perfluoro‐2‐phosphapropene with secondary amines in a 1:3 molar ratio affords the stable phosphaalkenes F3CPC(OR)NR2 (R = Me, Et) 1–4 in yields of 58%. NMR and He(I) PE spectroscopic investigations show that the lone pair electrons on nitrogen and oxygen participate in n/π conjugation. In contrast to typical low‐coordinated double bonds the new derivatives do not react with alcohols, amines, and 1,3‐dienes. The derivatives are more closely related to the phosphaalkenes F3C(F)NR2 than to perfluoro‐2‐phosphapropene. The reaction of F3C(OEt)NMe2 (3) with Cr(CO)5THF yields the η1(P) complex Cr(CO)5[F3CPC(OEt)NMe2] (7) with an unusually long sp2 PC bond (1.809 Å).

Arduengo, Anthony J.; Lattman, Michael; Dixon, David A.; Calabrese, Joseph C.

doi: 10.1002/hc.520020307pmid: N/A

The hypervalent phosphorus compound 3,7‐di‐t‐butyl‐5‐aza‐2,8‐dioxa‐1‐phosphabicyclo[3.3.0]octa‐2,4,6‐triene(ADPO), forms a monosubstituted adduct, ADPO·Fe(CO)4, by direct reaction of 10‐P‐3 ADPO with Fe2(CO)9 or Fe(CO)5, as well as by reaction of 1,1‐dichloro‐3,7‐di‐t‐butyl‐5‐aza‐2,8‐dioxa‐1‐phosphabicyclo[3.3.0]octa‐3, 6‐diene(ADPO·Cl2) with Na2[Fe(CO)4]. The X‐ray crystal structure of ADPO·Fe(CO)4 shows that ADPO is coordinated to the iron through the phosphorus. The phosphorus of the adduct has a tetrahedral 8‐P‐4 geometry in contrast to the planar T‐shaped geometry of uncomplexed 10‐P‐3 ADPO. Ultraviolet photolysis of ADPO·Fe(CO)4 yields the disubstituted species (ADPO)2·e(CO)3 wherein ADPO has dimerized via P–O bond cleavage to form a bidentate (ADPO)2 ligand containing a 10‐membered ring that bridges axial and equatorial positions at the trigonal bipyramidal iron center.

Hein, Joachim; Gärtner‐Winkhaus, Christiane; Nieger, Martin; Niecke, Edgar

doi: 10.1002/hc.520020308pmid: N/A

The reactions of chloro(2,4,6‐tri‐tert‐butylphenylimino)phosphane with lithium tris(trimethylsilyl)silanide and lithium diphenylketimide furnish products resulting from the incorporation of a second chloroiminophosphane molecule into the primary substitution product and subsequent nucleophilic displacement of the chlorine ligand. The final products have been characterized by X‐ray structure analyses, which revealed some remarkable features.

Al‐Rubaie, Ali Z.; Al‐Masoudi, Eman A.

doi: 10.1002/hc.520020309pmid: N/A

The synthesis and characterization of a new range of heterocyclic tellurium compounds based on 5,6‐dimethyl‐1,3‐dihydro‐2‐telluraindene are reported. Conductivity measurements of most compounds in dimethylsulfoxide (DMSO) and N,N‐dimethylformamide (DMF) showed considerable ionic character in both solvents. 1H and 13C NMR studies indicated that the telluronium salts are stable to reductive elimination and no reaction between solute and solvent was observed. Benzyl and allyl telluronium salts are exceptional. Infrared and mass spectral data are reported and discussed.

Sekiguchi, Masahito; Tanaka, Hiromichi; Takami, Noriaki; Ogawa, Akiya; Ryu, Ilhyong; Sonoda, Noboru

doi: 10.1002/hc.520020310pmid: N/A

The reduction of elemental selenium by samarium diiodide led to selective formation of selenolate anion species (Se2− and Se22−), the alkylation of which provided dialkyl selenides and diselenides, respectively, in excellent yields.