SU1731780A1 - Method of (dimethylalkoxysilyl)methyldiaryl(alkyl)phosphines synthesis - Google Patents

Abstract

Use: as ligands for creating graft and homogeneous catalysts, in particular for hydrogenation and hydrosilylation processes. The essence of the invention: the product - (dimethylethoxy-silyl) methyldiphenylphosphine (CH 3 ZKOSaH 3) - CH 2 P (C 5 H 2) 2, 50% yield, b.p. 118-120 ° C

Description

This invention relates to the chemistry of organophosphorus compounds, specifically to a new process for the preparation of (dimethylalkoxysilyl) methydiaryl (alkyl) phosphines of the general formula

Me2SiCH2PR 2

OR

where R is the primary or secondary n e most a kil.

R is aryl or alkyl.

(Dimethyl coxysilyl) methyl diary phospholipids are used as ligands to create various grafted and homogeneous catalysts, in particular for hydrogenation and hydrosilylation processes. The corresponding dilyl-phosphine derivatives are new and can also be used in the development of new efficient catalysts for various processes.

A characteristic feature of the phosphines of this general formula is the presence of a reactive alkoxy group on the silicon atom, which makes it possible to use these compounds for grafting catalytically active metal complexes onto various heterogeneous (silica gel, alumina, zeolites, etc.) and homogeneous (polysiloxanes) carriers.

WITH

V4 00 o

A known method for the synthesis of (dimethylalkoxysilyl) methyl diarylphosphines involves the interaction of diarylphosphide lithium with dimethylalkoxychloro methyl silane in a solution of heterogydrofuran at 0 ° C. In this case, lithium diarylphosphide is previously obtained as a result of the exothermic reaction of diarylchlorophosphine and lithium metal in a solution of tetrahydrofuran:

Ar, PLi + Me2SiCH2Ct Me2SiCH2P4r2 ORTHFOR

r2g

The described process for the preparation of (dimethylalkoxysilyl) methyl diarylphosphines has the following disadvantages. Working with lithium diaryl (alkyl) phosphides requires special measures for the deep cleaning of solvents and an inert gas from moisture and oxygen, as well as special fire safety measures. Due to the high nucleophilicity of diaryl- and especially lithium dialkylphosphides, their reactions with dimethylalkoxychloromethylsilanes are ambiguous both on the carbon atom and on the silicon atom. In the case of nucleophilic attack of lithium phosphide, an alkylphosphonite is obtained on the silicon atom, and (methyl methylalkoxysilyl) methylphosphine is not formed. For this reason, the yields of the target products in the described reaction do not exceed 30%. The high cost of lithium metal, its scarcity and flammability limit the widespread use of this method of synthesis.

The aim of the invention is to simplify the process of obtaining (dimethylalkoxy-silyl) methyldiaryl (alkyl) phosphines and to increase the yield of the target compounds,

The goal is achieved by the fact that dimethylalkoxychloromethyl silane and magnesium are boiled in tetrahydrofuran at boiling to obtain Grignard reagent followed by the interaction of this organomagnesium compound with diaryl (alkyl) chlorophosphine at -50-0 ° C, the ratio of reagents is 1: 1 in solution tetrashydrofuran in an inert gas atmosphere.

The Grignard reagent contains an alkoxyl group in the molecule, is stable and reacts with such strong electrophilic reagents as chlorophosphines, in the indicated temperature range exclusively at the carbon atom. The reaction at the oxygen center under these conditions practically does not occur. A decrease in temperature leads to an increase in the time of the process, and its increase (50%), bp. 118-120 ° C (6.03 mmHg). Pr20 1,5662. NMR31P (d, ppm): -23.73; NMR2351

to the occurrence of a side reaction at the oxygen center.

Example 1. (Dimethylethoxysilyl) methyl diphenylphosphine.

K 1.2 g (0.05 r-atom) of magnesium chips in

250 ml of absolute tetrahydrofuran was added 7.63 g (0.05 mol) of dimethylethoxychloromethylsilane, a crystal of iodine, and the mixture was heated under reflux with stirring for 3 hours. After dissolving the magnesium, the reaction mixture was cooled to -50 ° C and 11.03 g (0.05 mol) of diphenylchlorophosphine are added over 0.5 hours. The mixture is stirred for 1 hour at -50 ° C, then the temperature is raised to room temperature and the tetrahydrofuran is distilled off. The solid residue is extracted with a mixture of dry pentane (2 100 ml) and dry triethylamine (25.0 g). The precipitate is centrifuged, the solvents are distilled off, and the residue is distilled in vacuo. Yield 7.55 g

§Г

U, md., (O. 711U1G

(d. ppm): 13.95; 2J (PS) 16.85 Hz.

Example 2. (Dimethylethoxysilyl) methyldiphenylphosphine.

The synthesis was carried out as described in Example 1, but the addition of diphenylchlorophosphine to the Grignard reagent solution was carried out at -20 ° C. Yield 9.36 g (62%). Physicochemical constants, as well as NMR31P data and, as in Example 1,

Example 3. (Dimethylethoxysilyl) methyl diphenylphosphine.

The synthesis is carried out as described in Example 1, but the addition of a diphenyl chlorophosphine solution of the organomagnesium compound is carried out at 0 ° C. Yield 6.04 g (40%). Physico-chemical constants and spectral characteristics as in example 1.

Example 4. (Dimethylisopropoxysilyl) methyldiphenylphosphine.

Synthesis was carried out as in Example 2, but Grignard reagent was prepared from 1.2 g of 5 (0.05 g-atom) of magnesium and 8.33 g (0.05 mol) of dimethyl isopropoxychlormethylsilane. Yield 10.27 g (65%), bp. 170-171 ° C (1.5 mmHg), d420 1,0189. NMR31P (d, ppm): -22.67; NMR51 (d, ppm): 11.27; 2J (PSi) 17.52 Hz; 0 NMR13S-GN} (d, ppm): 0.55 d, 3J (PC) 3.29 Hz; (CH3) 2Si; 15.99 d, 1J (PC) 30.87 Hz, SiCH2P; 26.25 s, (СНзКН; 65.04 с, СНО: 128.4; 132.6; 141.7 - signals of arene cores 13С.

Example 5. (Dimethylethoxysilyl) methyldiisopropylphosphine.

The synthesis is carried out as in Example 2, but 7.63 g (0.05 mol) of diisopropyl chlorophosphine is added to a solution (dimethylethoxysilyl) methyl interglychloride in tetrahydrofuran cooled to -20 ° C. The product is isolated as described. The output 5.85 g (50%), so Kip, 42-44 ° C (0.01 mm Hg). to 20 1.4610, d42 ° 0.8849. NMR 31P fa, ppm): -5.33. NMR2951 (d, ppm): 14.59, 2J (PSi) 21.24 Hz; NMR13S-1H} (ppm): -0.29 d, 3J (PC) 4.00 Hz. (CH3bSl; 7.73 d, 1J (PC) 38.30 Hz. SlCH2P; 19.02 s, CH3CH2; 19.11; 20.06 d, 2J (PC) 11.90; 15.80 Hz, diastereotopic (CH3) 2CH; 25, 14 d, 1J (PC) 16.80 Hz. CHP; 58.40 s, CHaO.

Thus, the proposed method allows the reaction to be carried out using an organomagnesium compound that does not combust with air. In this way, (dimethyl alkoxysilyl) methydiaryl (alkyl) phosphines are obtained in a yield of up to 65% from readily available starting materials. Compounds of this type are of interest as components of catalytic systems.

Claims (1)

The invention The method of obtaining (dimethylalkoxyclyl) methyldiaryl (alkyl) phosphines of the general formula 0 five (CH3) 2SiCH2PR2 OR where R is the primary or secondary lower al kil.r R is aryl or alkyl, using dimethylalkoxychloromethylsilane and carrying out the process in tetrahydrofuran medium, characterized in that, in order to simplify the process and increase the yield of the target products, dimethylalkoxychloromethylsilane is reacted with magnesium in the medium of said solvent at boiling, forming organomagnesium compound with general formula (CH3 $ 1 sn2MdS1 OR treated with diaryl (alkyl) chlorophosphine of General formula Ra PCI, where R and R1 are as defined, at a temperature of from -50 to 0 ° C. five 0