Bis (trimethylsilyl) peroxide

from Wikipedia, the free encyclopedia
Structural formula
Structural formula of bis (trimethylsilyl) peroxide BTSP
General
Surname Bis (trimethylsilyl) peroxide
other names
  • BTSP
  • BTMSPO
Molecular formula C 6 H 18 O 2 Si 2
Brief description

clear colorless liquid or colorless oil

External identifiers / databases
CAS number 5796-98-5
PubChem 10058088
Wikidata Q50052005
properties
Molar mass 178.38 g mol −1
Physical state

liquid

density
  • 0.829 g cm −3
  • 0.841 g cm −3 at 20 ° C
boiling point
solubility

soluble in all common organic solvents

Refractive index

1.3970 at 20 ° C

safety instructions
GHS labeling of hazardous substances
02 - Highly / extremely flammable 05 - Corrosive 07 - Warning 08 - Dangerous to health

danger

H and P phrases H: 225-242-304-315-318-335-336-361-372-410
P: 201-210-234-264-280-301 + 310-302 + 352-304 + 340-305 + 351 + 338-307 + 311-313
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Bis (trimethylsilyl) peroxide is a derivative of the hydrogen peroxide H 2 O 2 in which both hydrogen atoms have been replaced by trimethylsilyl groups (TMS groups). The compound thus represents a 100%, anhydrous and TMS-protected form of H 2 O 2. BTMSPO is used for the oxidation of alcohols , ketones , phosphines , phosphites and sulfides and for electrophilic hydroxylations .

Manufacturing

The production of bis (trimethylsilyl) peroxide (referred to here as hexamethyl disilyl peroxide) was described in 1956, a solution of 85% or anhydrous hydrogen peroxide in diethyl ether being converted to BTSP with pyridine and chlorotrimethylsilane in 43% yield.

Synthesis of bis (trimethylsilyl) peroxide BTSP according to Hahn

The use of unstabilized, highly concentrated hydrogen peroxide, which is particularly prone to spontaneous explosions in the presence of heavy metal ions, should be avoided.

More modern syntheses of bis (trimethylsilyl) peroxide are based on anhydrous and solid hydrogen peroxide adducts as possible, which are treated with a silylating agent such as. B. trimethylchlorosilane TMS-Cl, hexamethyldisilazane HMDS or bis (trimethylsilyl) urea BSU can be reacted. An organic synthesis regulation is based on an older process description (with a yield of 35%) and delivers 1,4-diazabicyclo [2.2.2] octane and the unstable (and in the presence of transition metals ) after a laborious process with the expensive starting material DABCO tending to violent explosions) DABCO-H 2 O 2 adduct is a product contaminated with hexamethyldisiloxane in a maximum overall yield of 45%.

Synthesis of bis (trimethylsilyl) peroxide BTSP with DABCO hydrogen peroxide adduct

A process in which bis (trimethylsilyl) urea BSU with powdered carbamide peroxide (urea-hydrogen peroxide adduct ) gives BTSP in 86% pure yield after two distillation is suitable for producing larger quantities .

Synthesis of bis (trimethylsilyl) peroxide BTSP with urea-hydrogen peroxide adduct

However, this synthesis requires hexamethyldisilazane (for the production of BSU), which is significantly more expensive than trimethylchlorosilane, and is said to be inferior to a newer process in terms of reaction time and raw material costs in which the hydrogen peroxide- urotropin complex (in quantitative yield from hexamethylenetetramine and 30% H 2 O 2 ) reacted with TMS-Cl to form BSTP in a crude yield of 80%.

properties

Bis (trimethylsilyl) peroxide is a colorless oily liquid with a pungent odor that mixes with many organic solvents. The compound is much more stable than highly concentrated hydrogen peroxide and can be handled and distilled in its pure form. Since multiple explosive decomposition has been reported on contact with metals during manufacture by the pyridine and DABCO methods, BTSP should be handled with appropriate caution.

Applications

According to Dietmar Brandes, bis (trimethylsilyl) peroxide is a gentle and versatile oxidizing agent that z. B. thioethers are oxidized to sulfones , phosphines to phosphine oxides and phosphites to phosphates .

The oxidative cleavage of the sulfone group R 1 -SO 2 -R 2 (desulfonation) takes place with BTSP under gentle conditions with high yields.

Desulfonation with bis (trimethylsilyl) peroxide BTSP

With sulfur dioxide SO 2 , bis (trimethylsilyl) peroxide forms bis (trimethylsilyl) sulfate in quantitative yield, while with sulfur trioxide SO 3 in a molar ratio of 1: 1 to bis (trimethylsilyl) peroxomonosulfate, the trimethylsilyl ether of Caro's acid and in a molar ratio , which is unstable at 20 ° C 1: 2 reacts to form bis (trimethylsilyl) peroxodisulfate, which is also unstable.

Reactions of bis (trimethylsilyl) peroxide BTSP with sulfur trioxide

In contrast to Caro's acid, bis (trimethylsilyl) peroxomonosulfate, which is soluble in organic solvents, provides better yields than peroxomonosulfuric acid in the Baeyer-Villiger oxidation of ketones.

Baeyer-Villiger oxidation of 4-heptanone with bis (trimethylsilyl) peroxide BTSP

In the presence of catalytic amounts of trimethylsilyl trifluoromethanesulfonate TMSOTf, even more difficult oxidations such as. B. from cyclohexanone to ε-caprolactone in good yield (76%).

Baeyer-Villiger oxidation of cyclohexanone with bis (trimethylsilyl) peroxide BTSP

The use of ionic liquids as solvents and catalysts, such as e.g. B. 1-butyl-3-methyl-imidazolium trifluoromethylsulfonate BMIM-OTf, with ε-caprolactone from cyclohexanone in 94% yield when sodium trifluoromethanesulfonate is added.

In the working group of George A. Olah the electrophilic hydroxylation of aromatics with bis (trimethylsilyl) peroxide was worked on. In the presence of trifluoromethanesulfonic acid , mesitylene is converted into the corresponding phenol in 94% yield and toluene in 88% yield into the methylphenols with the isomer distribution ortho : 63%, meta : 10% and para: 27%.

Hydroxylation of toluene with bis (trimethylsilyl) peroxide BTSP

Barry Sharpless and co-workers developed a method for the epoxidation of olefins with bis (trimethylsilyl) peroxide and rhenium catalysts in dichloromethane , which is clearly superior to the reaction with methylrhenium trioxide CH 3 ReO 3 (MTO) and aqueous hydrogen peroxide. With much cheaper rhenium compounds, such as. B. rhenium (VII) oxide Re 2 O 7 and in the presence of traces of water or methanol , epoxide yields of over 90% can be achieved.

Epoxidation of stilbene with bis (trimethylsilyl) peroxide BTSP

Individual evidence

  1. ↑ a b c d P. Dembech, A. Ricci, G. Seconi, M. Taddei: Bis (trimethylsilyl) peroxide (BTMSPO) In: Organic Syntheses . 74, 1997, p. 84, doi : 10.15227 / orgsyn.074.0084 ; Coll. Vol. 9, 1998, p. 91 ( PDF ).
  2. ↑ a b c J.R. Hwu, B.-L. Chen: Bis (trimethylsilyl) peroxide . In: e-EROS Encyclopedia of Reagents for Organic Synthesis . 2001, doi : 10.1002 / 047084289X.rb219 .
  3. ↑ a b c Oakwood: [1] , accessed December 27, 2019
  4. ↑ a b c d W. Hahn, L. Metzinger: Organosilicon peroxides as initiators . In: Makromol. Chem. Band 21 , 1956, pp. 113–120 , doi : 10.1002 / macp.1956.020210109 .
  5. ↑ a b c d W.P. Jackson: A simple preparation of bis (trimethylsilyl) peroxide . In: Synlett . tape 9 , 1990, pp. 536 , doi : 10.1055 / s-1990-21157 .
  6. ↑ a b c B. Bressel, A. Blaschette: About peroxy compounds. VIII. Representation and properties of bis (trimethylsilyl) peroxomonosulfate and bis (trimethylsilyl) peroxodisulfate . In: Z. anorg. gen. Chem. Band 377 , no. 2 , 1970, p. 182-195 , doi : 10.1002 / zaac.19703770211 .
  7. ↑ a b c H. Neumann, D. Seebach: Bromine / lithium exchange on vinyl bromides with 2 mol equiv. tert ‐ butyllithium. Reactions of vinyl lithium compounds with hetero‐ and carbon electrophiles . In: Chem. Ber. tape 111 , no. 8 , 1978, p. 2785-2812 , doi : 10.1002 / cber.19781110807 .
  8. ^ PG Cookson, AG Davies, N. Fazal: The 1,4-diaza [2.2.2] bicyclooctane-hydrogen peroxide complex as a source of anhydrous hydrogen peroxide: The preparation of bis (trimethylsilyl) peroxides . In: J. Organomet. Chem. Band 99 , no. 2 , 1975, p. C31-C32 , doi : 10.1016 / S0022-328X (00) 88466-1 .
  9. ^ A b P. Babin, B. Bennetau, J. Dunoguès: A new practical preparation of bis (trimethylsilyl) peroxide . In: Synth. Commun. tape 22 , no. 19 , 1992, pp. 2849-2852 , doi : 10.1080 / 00397919208021551 .
  10. ↑ D. Brandes, A. Blaschette: About peroxo compounds. XI. Non-radical substitution and redox reactions of bis (trimethylsilyl) peroxide . In: J. Organomet. Chem. Band 49 , no. 1 , 1973, p. C6-C8 , doi : 10.1016 / S0022-328X (00) 84917-7 .
  11. ^ A b D. Brandes, A. Blaschette: About peroxo compounds. XII. Non-radical reactions of bis (trimethylsilyl) peroxide . In: J. Organomet. Chem. Band 73 , no. 2 , 1974, p. 217-227 , doi : 10.1016 / S0022-328X (00) 85638-7 .
  12. ↑ JR Hwu: A novel oxidative desulfonylation. Facile conversion of sulfones to aldehydes and ketones . In: J. Org. Chem. Band 48 , no. 23 , 1983, pp. 4432-4433 , doi : 10.1021 / jo00171a067 .
  13. ^ W. Adam, A. Rodriguez: Bis (trimethylsilyl) monoperoxysulfate: Convenient Baeyer-Villiger oxidant . In: J. Org. Chem. Band 44 , no. 26 , 1979, pp. 4969-4970 , doi : 10.1021 / jo00394a048 .
  14. ↑ M. Suzuki, H. Takada, R. Noyori: Bis (trimethylsilyl) peroxide for the Baeyer-Villiger type oxidation . In: J. Org. Chem. Band 47 , no. 5 , 1982, pp. 902-904 , doi : 10.1021 / jo00344a035 .
  15. ↑ S. Baj, A. Chrobok, R. Slupska: The Baeyer-Villiger oxidation of ketones with bis (trimethylsilyl) peroxide in the presence of ionic liquids as the solvent and catalyst . In: Green Chem. Band 11 , 2009, p. 279-282 , doi : 10.1039 / B814534B .
  16. ^ GA Olah, TD Ernst: Oxyfunctionalization of hydrocarbons. 14. Electrophilic hydroxylation of aromatics with bis (trimethylsilyl) peroxide / triflic acid . In: J. Org. Chem. Band 54 , no. 5 , 1989, pp. 1204-1206 , doi : 10.1021 / jo00266a041 .
  17. ^ AK Yudin, KB Sharpless: Bis (trimethylsilyl) peroxide extends the range of oxorhenium catalysts for olefin epoxidation . In: J. Am. Chem. Soc. tape 119 , no. 47 , 1997, pp. 11536–11537 , doi : 10.1021 / ja973043x .
  18. ^ AK Yudin, JP Chiang, H. Adolfsson, C. Copéret: Olefin epoxidation with bis (trimethylsilyl) peroxide catalyzed by inorganic oxorhenium derivatives. Controlled release of hydrogen peroxide . In: J. Org. Chem. Band 66 , no. 13 , 2001, p. 4713-4718 , doi : 10.1021 / jo010369m .