Protonenkatalysierte Spaltung von Enol‐phosphaten und phosphonaten

Pilgram, K.; Ohse, H.

doi:10.1002/ange.19660781705

Cited by 3 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thermal degradation of esters [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] was carried out at atmospheric pressure in the presence of catalytic amounts (0.01-0.1 mol %) of concentrated sulfuric acid or p-toluenesulfonic acid. A thermometer placed in the reaction medium permitted the temperature to be observed throughout the thermolysis.…”

Section: Results and Disucssionmentioning

confidence: 99%

“…Interestingly, the esters [1][2][3][4][5][6] were relatively stable when heated at 170-180°in the presence of catalytic amounts of concentrated sulfuric acid over a period of 2 hr. For example, ester 1 and 2 produced only traces of l,l,4,4-tetrachloro-l-buten-3-one.…”

Section: Results and Disucssionmentioning

confidence: 99%

“…In addition, water had collected in the receiver, presumably owing to dehydration of phosphoric acid.8 (12) R. Stroh and W. Hahn, "Methoden der Organischen Chemie/' "Houben-Weyl," Vol. 5/3, Georg Thieme Verlag, Stuttgart, 1962Stuttgart, , pp 511-1078 (13) K. Pilgram andH. Ohse, J. Org.…”

Section: Results and Disucssionmentioning

confidence: 99%

“…Found: C.40.0; H, 7.5; P, 16.8. 1,1,3,4,4,-Chlorine was passed into 1,1,4,4-tetrachloro-l-buten-3-one (20.8 g, 0.1 mol) under irradiation with ultraviolet light at 0°. After 1.5 hr, the crude product…”

Section: Socmentioning

confidence: 99%

See 3 more Smart Citations

Polychlorinated ketones. III. Formation by acid-catalyzed cleavage of vinyl phosphates and phosphonates

Pilgram¹,

Goergen²,

Ohse³

1969

J. Org. Chem.

View full text Add to dashboard Cite

Section: Results and Disucssionmentioning

confidence: 99%

Section: Results and Disucssionmentioning

confidence: 99%

Section: Results and Disucssionmentioning

confidence: 99%

Section: Socmentioning

confidence: 99%

See 2 more Smart Citations

Polychlorinated ketones. III. Formation by acid-catalyzed cleavage of vinyl phosphates and phosphonates

Pilgram¹,

Goergen²,

Ohse³

1969

J. Org. Chem.

View full text Add to dashboard Cite

“…Acid-catalysed cleavage of the isopropyl or sec-butyl ester (5) at 170 "C, however, gives a 70 % yield of the ketone within a few minutes. It is probable that the phosphonium ion (7) formed as intermediate by protonation decomposes by way of an enol phosphoric acid and a carbonium ion into the ketone (2), metaphosphate, olefin (3), and a proton: there is a common intermediate whose retention time in gas chromatography lies between those of (1) and ( 2 ) ; this compound is most likely perchloro(ethy1 vinyl ketone).…”

Section: Proton-catalysed Cleavage Of Enol Phosphates and Phosphonatesmentioning

confidence: 99%

Proton‐Catalysed Cleavage of Enol Phosphates and Phosphonates

Pilgram¹,

Ohse²

1966

Angew. Chem. Int. Ed. Engl.

Self Cite

View full text Add to dashboard Cite

Reduction of an ethereal solution of chloropentakis(trifluoro-ph0sphine)rhenium [21 (0.12 niole/l) with an excess of about 1 7; potassium amalgam at 20 "C affords potassium pentakis-(trifluorophosphine)rhenate, which on treatment with 88 % phosphoric acid forms HRe(PF&, thc first hydrido-trifluorophosphine complex of a group VIIA metal. Use of D3P04 affords the analogous deuterido compound. CHI C2Hs C2H5 CH3 CH3 CH3 CH3 CHI HRe(PF3)5 is, however, also directly accessible, in 40 % yield, by reduction of ReCIs with Cu powder (molar ratio ca. 1 : 40) at 300 OC with a PF3 pressure of 250 atm and a H2 pressure of 100 atm. It is purified by sublimation. Hydridopentakis(trifluorophosphine)rhenium resembles the monohydrido compounds HM(PF3)4 of cobalt and iridium [31 in its high thermal and chemical stability. The colorless, centimeter-long needles of this hydrophobic compound (m.p. 42OC, decomp. from 160°C) sublime at 2O0C/1O mm and are stable for several days in dry air. The covalent nature of the Re-H bond is confirmed by an intense Re-H stretching vibration at 1882 (m) cm-1[41 [GR~-D = 1346 (m) cm-11 and the strong chemical shift to high field of its broad 1H-NMR signal (no fine structure)[sl (8 = 8.2 ppm; TMS as internal standard). The P-F vibrations are at 971(w), 918 (vs), 877 (s), 869 (s), and 860 (m-s) cm-1.

show abstract

Dehalogenation of Perchloroketones with Triphenylphosphine or Trialkyl or Triaryl Phosphites

Pilgram¹,

Ohse²

1966

Angew. Chem. Int. Ed. Engl.

View full text Add to dashboard Cite

Perchlorodivinyl ketone (21, b.p. 69 'C/O.3 mm, n'," = 1.5661, d20 = 1.6963121, is readily obtained (yield 91.2 %) by treatment of perchloro-3-pentanone ( I ) , b.p. 94-95 "C10.6 mm, ng = 1.5682, with triphenylphosphine in ether at 5 to 35°C. The triphenylphosphine dichloride formed is advantageously converted into triphenylphosphine oxide by addition of water before isolation of the ketone ( 2 ) . Trimethyl phosphite and ( I ) afford dimethyl phosphorochloridate (yield 100 %) as well as the ketone (2) (yield 95.3 %). With both reagents there is a common intermediate whose retention time in gas chromatography lies between those of (1) and ( 2 ) ; this compound is most likely perchloro(ethy1 vinyl ketone). $C12 cc1By analogy with the mechanism of dehalogenationtzl of cc,@-dibromo compounds with trialkyl phosphites [3,41 and triphenylphosphine [51, we assume that the phosphine (or phosphite) first removes the chlorine atom cc to the carbonyl group, this being followed by loss of a P-chlorine atom as an anion. Perchlorobutanone (3) reacts equally smoothly with triphenylphosphine in ethereal solution and, after addition of water, gives 1,1,3,4,4-pentachloro-3-buten-2-one (yield 82.1 %; b.p. 89OC/9 mm, n'," = 1.5440, d20 = 1.6628; ref.[61: b.p. 99-100 "C, n'," = 1.5442). Trichloromethyl trichlorovinyl ketone (4) is formed in the first step of this reaction. A second mole of triphenylphosphine then reacts with (4) to give an enol phosphonium salt (S), which is extremely sensitive to solvolysis and with water decomposes to 1,1,3,4,4-pentachloro-3-buten-2-one (6), triphenylphosphine oxide, and HCl. The ketone (4) is identical with a sample prepared by a different route"]. Trialkyl phosphites react with (3) by an analogous first step, which leads to (4), alkyl chloride, and dialkyl phosphorochloridate; then a second mole of trialkyl phosphite brings about a Perkow reaction. OP(CSH5)S ClzHC-6-CCl=CC1_' " = A -c c 1 = C c l 2 C P An excess of triphenyl phosphite has no influence, so that the product (4) can be distilled continuously when the mixture is heated in an oil bath.[ (3b), respectively, which can be used for aminomethylations [21. Preparation of N-Functional

show abstract

Protonenkatalysierte Spaltung von Enol‐phosphaten und phosphonaten

Cited by 3 publications

References 0 publications

Polychlorinated ketones. III. Formation by acid-catalyzed cleavage of vinyl phosphates and phosphonates

Polychlorinated ketones. III. Formation by acid-catalyzed cleavage of vinyl phosphates and phosphonates

Proton‐Catalysed Cleavage of Enol Phosphates and Phosphonates

Dehalogenation of Perchloroketones with Triphenylphosphine or Trialkyl or Triaryl Phosphites

Contact Info

Product

Resources

About