Process for the reduction of a tertiary phosphine oxide to the corresponding tertiary phosphine in the presence of a catalyst and use of a tertiary phosphine for reducing a tertiary phosphine oxide in the presence of a catalyst

1. A process for the conversion of a tertiary phosphine oxide to the corresponding tertiary phosphine comprising reacting said tertiary phosphine oxide with a reducing tertiary phosphine, in the presence of a halogen-containing compound as a catalyst that catalyzes the conversion.

2. A process according to claim 1 , wherein a tertiary phosphine oxide of formula (I)

wherein

each R 1 , R 2 and R 3 is independently selected from the group consisting essentially of substituted or unsubstituted, branched or linear hydrocarbyl; and substituted or unsubstituted carbocyclyl or heterocyclyl;

A is a linking moiety;

m is an integer of from 0 to 2;

is converted into the corresponding tertiary phosphine of formula (III)

wherein R 1 , R 2 , R 3 , A and m are as defined herein above;

by reaction with a reducing tertiary phosphine of formula (II)

wherein

each R 4 , R 5 and R 6 is independently selected from the group consisting essentially of substituted or unsubstituted, branched or linear hydrocarbyl; and substituted or unsubstituted, aliphatic or aromatic carbocyclyl or heterocyclyl;

B is a linking moiety; and

n is an integer of from 0 to 2;

in the presence of a catalyst for the reaction.

3. The process according to claim 2 , wherein each A and B is independently selected from substituted or unsubstituted hydrocarbylene, substituted or unsubstituted monocyclic or polycyclic carbocyclylene, substituted or unsubstituted monocyclic or polycyclic heterocyclylene and substituted or unsubstituted metallocenylene.

4. The process according to claim 1 , wherein the catalyst is selected from the group consisting essentially of chlorine, bromine, iodine, cyanuric chloride, tetrahalomethanes, and phosphine dihalides.

5. The process according to claim 1 , wherein the process is performed under solvent-free conditions or in an anhydrous aprotic solvent.

6. The process according to claim 5 , wherein the anhydrous aprotic solvent is selected from the group consisting essentially of tetrahydrofuran, acetonitrile, diethylether, propionitrile, toluene, ethyl acetate and mixtures of these.

7. The process according to claim 1 , wherein the reducing tertiary phosphine is added to the reaction mixture at a molar ratio of the phosphine function(s) of the reducing tertiary phosphine to the phosphine oxide function(s) of the tertiary phosphine oxide of at least 1.

8. The process according to claim 1 , wherein the basicity of the reducing tertiary phosphine is greater than the basicity of the product tertiary phosphine.

9. The process according to claim 1 , wherein the tertiary phosphine oxide to be reduced is attached to a solid support.

10. The process according to claim 1 , wherein the reducing tertiary phosphine is attached to a solid support.

11. The process according to claim 2 , wherein the catalyst is selected from the group consisting essentially of chlorine, bromine, iodine, cyanuric chloride, tetrahalomethanes, and phosphine dihalides.

12. The process according to claim 3 , wherein the catalyst is selected from the group consisting essentially of chlorine, bromine, iodine, cyanuric chloride, tetrahalomethanes, and phosphine dihalides.

13. The process according to claim 2 , wherein the process is performed under solvent-free conditions or in an anhydrous aprotic solvent.

14. The process according to claim 3 , wherein the process is performed under solvent-free conditions or in an anhydrous aprotic solvent.

15. The process according to claim 4 , wherein the process is performed under solvent-free conditions or in an anhydrous aprotic solvent.