4-Phenylsulfonyl-2-butanone Ethylene Acetal

[56161-54-7]  · C12H16O4S  · 4-Phenylsulfonyl-2-butanone Ethylene Acetal  · (MW 256.35)

(a reagent for synthesizing various derivatives of 2-alkanones)

Alternate Name: PSB-EA.

Physical Data: colorless crystals; mp 33-34 °C or 41-42 °C.1,2

Preparative Method: by the Michael addition of benzenesulfinic acid (see Sodium Azide) to 3-buten-2-one followed by acetalization with ethylene glycol.1,2

Synthesis of 2-Alkanones and 3-Alken-2-one.

Monoalkylation of 4-phenylsulfonyl-2-butanone ethylene acetal (1) takes place at the position a to the phenylsulfonyl group on successive treatment with n-Butyllithium and then with an alkyl halide (or tosylate). Deprotection of the acetal group and subsequent elimination of the benzenesulfinic acid moiety with a base transforms the monoalkylation product to the corresponding 3-alken-2-one (eq 1).1,3 A 2-alkanone is obtainable from the monoalkylation product by reductive desulfurization and subsequent acidic deprotection (eq 2).2-5

Alkane-2,5-dione Synthesis.

On treatment with n-BuLi and an acyl chloride, (1) affords an a-acylated product, which easily undergoes reductive desulfurization with Aluminum Amalgam or Sodium Amalgam. Deprotection forms an alkane-2,5-dione (eq 3).6,7

Synthesis of 6-Hydroxy-2-alkanones.

The lithio derivative of (1) reacts with a terminal epoxide to give a ring-opened product. Acidic deprotection of the product forms 6-hydroxy-2-alkanone which cyclizes to give a d-lactol (eq 4).8

Related Reagents.

3-(Phenylsulfonyl)propanal Ethylene Acetal.

1. Kondo, K.; Tunemoto, D. TL 1975, 1007.
2. Wershofen, S.; Classen, A.; Scharf, H. D. LA 1989, 9.
3. Fürst, A.; Labler, L.; Meier, W. HCA 1982, 65, 1499.
4. Kato, T.; Takayanagi, H.; Uyehara, T.; Kitahara, Y. CL 1977, 1009.
5. Wershofen, S.; Scharf, H. D. S 1988, 854.
6. Kondo, K.; Tsunemoto, D. TL 1975, 1397.
7. Paquette, L. A.; Galemmo, R. A., Jr.; Caille, J. C.; Valpey, R. S. JOC 1986, 51, 686.
8. Kondo, K.; Saito, E.; Tunemoto, D. TL 1975, 2275.

Katsuyuki Ogura

Chiba University, Japan

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