[33861-17-5] · C9H14SeSi · Phenyl Trimethylsilyl Selenide · (MW 229.28)
Physical Data: bp 92-93 °C/5 mmHg. 1H NMR (CDCl3) d 0.35 (Me3Si); 13C NMR (CDCl3) d 1.49 (Me3Si).
Solubility: sol benzene, Et2O, THF, MeCN.
Preparative Methods: conveniently prepared by the reduction of Diphenyl Diselenide with Sodium in THF, followed by silylation of thus formed PhSeNa with Chlorotrimethylsilane.1a,b In a small scale reaction, silylation of PhSeLi, which can be prepared in situ from metallic Selenium and Phenyllithium in THF, is alternatively utilized.1c
Purification: distillation under reduced pressure.
Handling, Storage, and Precautions: although phenyl trimethylsilyl selenide isolated as a colorless liquid is somewhat sensitive to atmospheric moisture, it can be handled conveniently using syringe techniques and can be stored indefinitely under dry nitrogen (or argon). Use in a fume hood.
Phenyl trimethylsilyl selenide does not react with carbonyl compounds at 25 °C or on heating. However, use of Aluminum Chloride as catalyst results in selective formation of selenoacetals, whereas the copresence of zinc halide in place of AlCl3 leads to O-(trimethylsilyl) monoselenoacetals,2a-d which can be utilized as a-siloxy radical precursors (eq 1).2e
In the presence of a catalytic amount of Zinc Iodide, alkyl acetates and lactones react with phenyl trimethylsilyl selenide to afford alkyl phenyl selenides and o-(phenylseleno)carboxylic acids, respectively (eq 2).3
Conjugate addition of phenyl trimethylsilyl selenide to a,b-unsaturated aldehydes and ketones has been attained by using Triphenylphosphine,2c Zinc Chloride,2c or Trimethylsilyl Trifluoromethanesulfonate4 as the catalyst. Combination of this reaction with selenoxide elimination5 provides a one-pot procedure for a-alkoxyalkylation of a,b-unsaturated ketones (eq 3).
Ring opening of epoxides, oxetanes, and tetrahydrofurans with phenyl trimethylsilyl selenide takes place in the presence of ZnI2 to provide b-, g-, and d-siloxyalkyl phenyl selenides, respectively, in good yields (eq 4).6
Introduction of a phenylseleno function into organic molecules has also been attained by the reaction of phenyl trimethylsilyl selenide with organic halides.7 Palladium-catalyzed addition of PhSeSiMe3 to arylacetylenes takes place regio- and stereoselectively to give b-silyl substituted vinylic selenides (eq 5).8 PhSeSiMe3 serves as a mild reducing agent for deoxygenation of sulfoxides, selenoxides, and telluroxides.9
PhTeSiMe3 is synthesized by the reaction of Me3SiCl with PhTeLi,10a PhTeNa,10b or PhTeMgBr,10c and is purified by distillation (bp 77-79 °C/2 mmHg). It can be stored as a 2.5 M hexane solution in a Schlenk flask. Like PhSeSiMe3, PhTeSiMe3 reacts with cyclic ethers and lactones to give ring-opened products.10b Upon treatment with MeOH, benzenetellurol is formed in situ.10d
Osaka University, Japan