Process for the preparation of acylphosphines, acyl oxides and acyl sulfides
View Patent ↗A description is given of processes for the preparation of mono- and bisacylphosphines and of mono- and bisacylphosphine oxides and mono- and bisacylphosphine sulfides, which comprises first reacting organic P-monohalogenophosphines or P,P-dihalogenophosphines, or mixtures thereof, with an alkali metal or magnesium in combination with lithium, where appropriate in the presence of a catalyst, and then carrying out the reaction with acid halides and, in the case of the process for the preparation of oxides, carrying out an oxidation step and, in the case of the preparation of sulfides, reacting the phosphines so obtained with sulfur. It is characteristic, inter alia, that the processes are carried out without isolation of the intermediates.
1. A process for the preparation of acylphosphine oxides and acylphosphine sulfides of formula IV
n=1, m=2, and
R 1 is C 1 -C 18 alkyl, C 2 -C 18 alkyl which is interrupted by one or several non-successive O atoms;
phenyl-substituted C 1 -C 4 alkyl, C 2 -C 8 alkenyl, phenyl, naphthyl, biphenyl, C 5 -C 12 cycloalkyl, the groups phenyl, naphthyl, biphenyl, C 5 -C 12 cycloalkyl being unsubstituted or substituted by one to five halogen, C 1 -C 8 alkyl, C 1 -C 8 alkylthio and/or C 1 -C 8 alkoxy;
Z is O or S,
R 2 is C 1 -C 18 alkyl, C 3 -C 12 cycloalkyl, C 2 -C 18 alkenyl, phenyl, naphthyl, biphenyl, the groups phenyl, naphthyl, biphenyl being unsubstituted or substituted by one to four C 1 -C 8 alkyl, C 1 -C 8 alkoxy, C 1 -C 8 alkylthio and/or halogen;
R 3 is C 1 -C 18 alkyl, C 2 -C 18 alkyl which is interrupted by one or several non-successive O atoms;
phenyl-substituted C 1 -C 4 alkyl, C 2 -C 8 alkenyl, phenyl, naphthyl, biphenyl, C 5 -C 12 cycloalkyl, the groups phenyl, naphthyl, biphenyl, C 5 -C 12 cycloalkyl being unsubstituted or substituted by one to five halogen, C 1 -C 8 alkyl, C 1 -C 8 alkylthio and/or C 1 -C 8 alkoxy;
by
(1) reacting organic phosphorus halides of formula II
wherein R 1 , R 3 , n and m have the meaning cited above and Y is Br or Cl,
with an alkali metal or with magnesium in combination with lithium, or with mixtures thereof, with or without a catalyst, and
(2) subsequent reaction with m acid halides of formula III
wherein R 2 , m and Y have the meaning cited above, and
(3) oxidation or reaction with sulfur of the acylphosphine of formula I
which is obtained by reaction (2),
wherein R 1 , R 2 , R 3 , m and n have the meaning cited above,
which process is carried out without isolation of the intermediates.
2. A process according to claim 1 , wherein
R 1 , is C 1 -C 12 alkyl, cyclohexyl, phenyl or biphenyl, the groups phenyl and biphenyl being unsubstituted or substituted by one to four C 1 -C 8 alkyl and/or C 1 -C 8 alkoxy;
R 3 is C 1 -C 12 alkyl, cyclohexyl, phenyl or biphenyl, the groups phenyl and biphenyl being unsubstituted or substituted by one to four C 1 -C 8 alkyl and/or C 1 -C 8 alkoxy.
3. A process according to claim 1 , wherein R 2 is phenyl which is substituted in 2,6- or 2,4,6-position by C 1 -C 4 alkyl and/or C 1 -C 4 alkoxy.
4. A process according to claim 1 , wherein Y in formula II is chloro.
5. A process according to claim 1 , wherein the reaction (1) is carried out using lithium, sodium or potassium.
6. A process according to claim 5 , wherein from 4 to 6 atom equivalents of the alkali metal are used for the preparation of compounds of formula I, wherein m is 2.
7. A process according to claim 1 , wherein Y in the compounds of formula III is chloro.
8. A process according to claim 1 , which comprises carrying out the reaction (1) in the presence of a catalyst.
9. A process according to claim 1 , which comprises carrying out the reaction (1) of the organic phosphorus halides (II) with an alkali metal in the temperature range from −20° to +120° C.
10. A process according to claim 1 , which comprises carrying out the reaction (1) of the organic phosphorus halides (II) with magnesium in combination with an alkali metal in the temperature range from 80° to 120° C.
11. A process according to claim 1 , wherein the reaction (2) of the metallized phosphine with the acid chloride (III) is carried out at −20° to +80° C.
12. A process according to claim 1 , wherein the reaction steps (1) and (2) are carried out in the same solvent.
13. A process according to claim 1 , wherein, in formula I, n is 1, m is 1, R 1 is phenyl which is unsubstituted or substituted by C 1 -C 4 alkyl or C 1 -C 8 alkoxy, or R 1 is C 1 -C 12 alkyl; R 2 is phenyl which is substituted by halogen, C 1 -C 4 alkoxy or C 1 -C 4 alkyl; and R 3 is unsubstituted or C 1 -C 4 alkyl-substituted phenyl.