Allyl Phenyl Selenide1

[14370-82-2]  · C9H10Se  · Allyl Phenyl Selenide  · (MW 197.14)

(metalated derivatives are ambident nucleophiles;2,4,6-9,11,15 sigmatropic rearrangements produce allyl alcohols and amines;9-12 cleavage of Se-C bond provides a source of allyl anions,13 cations,6,14,15 and radicals16,17)

Alternate Name: (2-propenylseleno)benzene.

Physical Data: bp 65-68 °C/1 mmHg;2 82-83 °C/3 mmHg.3

Solubility: insol water; sol most organic solvents.

Preparative Methods: from Allyl Bromide,2,4 chloride, or mesylate4 and sodium benzeneselenolate (prepared by reduction of Diphenyl Diselenide,2,4 or deprotonation of Benzeneselenol).3 Numerous other procedures have been used, including the reaction of allylsilanes with Benzeneselenenyl Chloride,5a allyl acetates with Phenyl Trimethylsilyl Selenide,5b allyl halides with PhSeTl,5c and allylamines with PhSeLi (Ru catalyzed).5d

Purification: distillation in vacuo2,3 or chromatography on silica gel4 before use.

Handling, Storage, and Precautions: the compound is stable indefinitely in the freezer, but will slowly turn yellow at room temperature and in ambient light due to the formation of diphenyl diselenide. The compound is not excessively malodorous when pure, but should be prepared and handled in a fume hood due to the toxic nature of many organoselenium compounds.

Metalation.

Allyl phenyl selenide (1) is metalated with Lithium Diisopropylamide in THF at -78 °C (eq 1).6,7 The 1-phenyselenoallyllithium (2) formed reacts principally at the a-position with alkyl halides and epoxides,6 and at the g-position with aldehydes and ketones.6,8 If (2) is treated with Triethylaluminum prior to reaction with carbonyl compounds, mainly a-hydroxyalkylation is observed.8 Representative regioselectivities are shown in eq 2.

Altered reactivity and well-defined regioselectivity can also be achieved by prior conversion to phenylselenoallylstannanes (3), which react at the a-position with cationic electrophiles such as iminium salts (eq 3).9

Like other stabilized organolithium reagents, (2) adds predominantly 1,2 to enones such as cyclopentenone in THF (1,2-adduct, a:g = 62:18; 1,4-adduct, a:g = 10:8) but gives exclusively 1,4-addition (a:g = 81:5) when 1 equiv of Hexamethylphosphoric Triamide is added.2

[2,3] Sigmatropic Rearrangements.

A common application of allylic selenides is oxidation to form transient selenoxides, which undergo facile [2,3] sigmatropic rearrangement at low temperatures. In contrast to sulfur analogs, where the sulfoxide is usually favored, the equilibrium strongly favors the selenenate esters over the selenoxide,10 so the rearrangement is very clean, requires no trapping reagents, and can typically be performed at 0 °C or lower.

An interesting extension is amination, in which allyl selenides are treated with an N-chloroamine (such as anhydrous Chloramine-T) or primary amide or carbamate in the presence of N-Chlorosuccinimide. This forms the selenimide in situ, which rearranges to an N-allylsulfonamide, -amide, or -carbamate (eq 4).11

Allylselenonium ylides also undergo sigmatropic rearrangements. The diazo-b-lactam (4) reacts with (1) with copper catalysis to form the allylated selenide (5) (eq 5).12

Allylic Rearrangement of Allyl Selenides.

Unsymmetrically substituted allyl selenides undergo easy allylic isomerization on irradiation or with acid catalysis, usually to favor primary over secondary selenides.9,11 Such processes can be applied to the alkylation products of (2) to effect regiocontrolled further transformations, such as a second metalation and alkylation,11 or oxidative,9 or aminative [2,3] sigmatropic rearrangements.11 Eq 6 presents an example involving an aminomethylated methallyl selenide.9

Allyl Phenyl Selenide as an Allylation Reagent.

The relatively weak C-Se bond in (1) and its alkylation products can be exploited to produce anionic and cationic allyl synthons. Treatment of (1) with n-Butyllithium results in Li/Se exchange to form Allyllithium. Other allyl selenides also work.13

Allyl selenides (3) undergo coupling with organocuprates6 and Grignard reagents in the presence of nickel catalyst.14 The reaction of (1) with Triethylborane forms the alkylated allylboronate (6) by B to C alkyl transfer with displacement of the PhSe group. This boronate complex can be trapped with aldehydes, or allowed to rearrange to (7) before trapping, to give regioisomeric homoallyl alcohols (8) and (9), in ratios of 94:6, and 9:91, respectively (eq 7).15

There are also reports of allyl radical transfer from (1) to carbon16 and sulfur (sulfonyl) centered radicals.17

Related Reagents.

Allyl Phenyl Sulfide.


1. Reich, H. J. In Organoselenium Chemistry; D. Liotta, Ed.; Wiley: New York, 1987, pp 243, 365. Clive, D. L. J. T 1978, 34, 1049. Reich, H. J. AC(R) 1979, 12, 22.
2. Binns, M. R.; Haynes, R. K. JOC 1981, 46, 3790.
3. Kataev, E. G.; Kataeva, L. M.; Chmutova, G. A. JOU 1966, 2, 2200; CA 1967, 66, 75 790.
4. Shea, R. G.; Fitzner. J. N.; Fankhauser, J. E.; Spaltenstein, A.; Carpino, P. A.; Peevey, R. M.; Pratt, D. V.; Tenge, B. J.; Hopkins, P. B. JOC 1986, 51, 5243.
5. (a) Nishiyama, H.; Itagaki, K. Sakuta, K. Itoh, K. TL 1981, 22, 5285. (b) Miyoshi, N.; Ishii, H.; Murai, S.; Sonoda, N. CL 1979, 873. (c) Detty, M. R.; Wood, G. P. JOC 1980, 45, 80. (d) Murahashi, S.-I.; Yano, T. JACS 1980, 102, 2456.
6. (a) Reich, H. J. JOC 1975, 40, 2570. (b) Reich, H. J.; Willis, W. W.; Clark, P. D. JOC 1981, 46, 2775.
7. Nishitani, K.; Mimaki, Y.; Sato, K.; Yamakawa, K. CPB 1992, 40, 288.
8. Yamamoto, Y.; Yatagai, H.; Saito, Y.; Maruyama, K. JOC 1984, 49, 1096.
9. Reich, H. J.; Schroeder, M. C., Reich, I. L. Isr. J. Chem. 1984, 24, 157.
10. Reich, H. J.; Yelm, K. E.; Wollowitz, S. JACS 1983, 105, 2503.
11. Spaltenstein, A.; Carpino, P. A.; Miyake, F.; Hopkins, P. B. JOC 1987, 52, 3759.
12. (a) Giddings, P. J.; John, D. I.; Thomas, E. J. TL 1980, 21, 395. (b) Giddings, P. J.; John, D. I.; Thomas, E. J. JCS(P1) 1982, 2757.
13. Clarembeau, M.; Krief, A. TL 1984, 25, 3629.
14. Oakamura, H.; Miura, M.; Kosugi, K.; Takei, H. TL 1980, 21, 87.
15. Yamamoto, Y.; Saito, Y.; Maruyama, K. JOC 1983, 48, 5408.
16. Barton, D. H. R.; Crich, D. JCS(P1) 1986, 1613.
17. Kamigata, N.; Ishii, K.; Ohtsuka, T.; Matsuyama, H. BCJ 1991, 64, 3479.

Ieva L. Reich & Hans J. Reich

University of Wisconsin, Madison, WI, USA



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