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Synlett 2011(15): 2248-2252  
DOI: 10.1055/s-0030-1261195
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Organoselenosilane-Mediated Selective Mild Access to Selenolesters, Selenoanhydrides and Diacyl Diselenides

Antonella Capperucci*, Alessandro Degl’Innocenti*, Caterina Tiberi
Department of Chemistry ‘Ugo Schiff’, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino (Firenze), Italy
Fax: +39(055)4573585; e-Mail: alessandro.deglinnocenti@unifi.it;
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Publication History

Received 20 June 2011
Publication Date:
24 August 2011 (online)

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Organoselenosilane-Mediated Selective Mild Access to Selenolesters, Selenoanhydrides and Diacyl DiselenidesSynlett 2012; 2012(04): 644-644
DOI: 10.1055/s-0031-1290361

Abstract

Reaction of acyl chlorides with phenylselenotrimethyl­silane promoted by TBAF afforded a mild general access to selenolesters in good yields. When acyl chlorides were reacted with bis(trimethylsilyl)selenide (HMDSS) in 2:1 or 1:1 ratio a selective entry to selenoanhydrides or diacyl diselenides respectively was obtained.

Key words

selenosilanes - selenolesters - diacyl selenides - diacyl diselenides - fluoride ion

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Preparation of Se-Phenyl 2-chloropropaneselenoate (3f): To a solution of 2-chloropropanoyl chloride (30 mg, 0.24 mmol) in anhyd THF (0.5 mL) was added under an inert atmosphere phenylselenotrimethylsilane (71 µL, 0.28 mmol). TBAF (50 µL, 1 M THF solution, 0.05 mmol) was added dropwise at 0 ˚C. The reaction was warmed to r.t. and stirred overnight. The mixture was then extracted with Et2O, washed with brine and dried over Na2SO4. Filtration and evaporation of the solvent gave the crude 3f as a yellow oil, which was purified by TLC on silica gel (n-hexane-CH2Cl2, 2:1). Yield: 63%. ¹H NMR (200 MHz, CDCl3): δ = 1.75 (d, 3 H, J = 7.0 Hz), 4.58 (q, 1 H, J = 7.0 Hz), 7.43-7.46 (m, 3 H), 7.51-7.55 (m, 2 H). ¹³C NMR (50 MHz, CDCl3): δ = 22.1, 63.7, 127.5, 129.3, 130.6, 131.3, 200.4. 77Se (38 MHz, CDCl3): δ = 650.6. MS: m/z (%) = 248 (26) [M+], 192 (22), 158 (39), 91 (44), 78 (55), 63 (100).

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Synthesis of 4-Methoxybenzoic Selenoanhydride (5c): A solution of 4-methoxybenzoyl chloride (24 µL, 0.18 mmol) and TBAF (1 M in THF, 18 µL, 0.018 mmol) in anhyd THF (0.5 mL) was cooled under atmosphere at 0 ˚C, and treated dropwise with bis(trimethylsilyl)selenide (HMDSS; 21 mg, 0.09 mmol). The red mixture turned to pale yellow after few minutes. After warming to r.t., and stirring for 2 h, the solution was diluted with Et2O, washed with brine and dried over Na2SO4. The crude product was purified by flash column chromatography (n-hexane-CH2Cl2, 1:1) to afford 5c as a yellow solid (24 mg, 75%). ¹H NMR (200 MHz, CDCl3): δ = 3.88 (s, 6 H), 6.93-6.98 (m, 4 H), 7.92-7.96 (m, 4 H). ¹³C NMR (50 MHz, CDCl3): δ = 55.6, 114.1, 130.9, 131.5, 164.5, 185.9. 77Se (38 MHz, CDCl3): δ = 730.0.

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Preparation of 4-Methoxybenzoic Diselenoperoxy-anhydride (6c): A solution of 4-methoxybenzoyl chloride (24 µL, 0.18 mmol) in anhyd THF (0.5 mL) was added under an inert atmosphere with HMDSS (44 mg, 0.19 mmol) and it was cooled to 0 ˚C. TBAF (1 M in THF, 38 µL, 0.038 mmol) was then added dropwise. The red mixture so formed was warmed to r.t. and stirred for 2 h. Upon quenching with brine, the red solution turned slowly to pale yellow. Extraction with Et2O, drying over Na2SO4 and removal of the solvent under vacuum afforded the crude product, which was purified by flash column chromatography (n-hexane-CH2Cl2, 1:1) to produce 6c as a yellow solid (55 mg, 71%). ¹H NMR (200 MHz, CDCl3):
δ = 3.88 (s, 6 H), 6.92-6.98 (m, 4 H), 7.91-8.07 (m, 4 H). ¹³C NMR (50 MHz, CDCl3): δ = 55.6, 114.2, 129.3, 130.5, 164.4, 186.9. 77Se (38 MHz, CDCl3): δ = 598.5.