Methyl Benzenesulfinate1

(1; R = H)

[670-98-4]  · C7H8O2S  · Methyl Benzenesulfinate  · (MW 156.22) (R)-(1)

[111698-33-0] (S)-(1)

[112425-42-0] (±)-(1)

[114376-00-0] (2; R = Me)

[672-78-6]  · C8H10O2S  · Methyl p-Toluenesulfinate  · (MW 170.25) (R)-(2)

[64396-66-3] (S)-(2)

[59203-01-9] (±)-(2)

[59153-37-6] (-)-(2)

[69979-69-7] (+)-(2)


(synthesis of sulfinyl compounds;2 preparation of menthyl arenesulfinates3)

Physical Data: (1) bp 76-78 °C/0.45 mmHg; n25D 1.5436; d 1.1948 g cm-3. (2) bp 129-130 °C/14 mmHg; n25D 1.5405; d 1.1498 g cm-3.

Solubility: (both compounds) sol alcohol, Et2O, benzene; insol H2O.

Preparative Methods: prepared by oxidation of Diphenyl Disulfide (or p-tolyl disulfide) with Lead(IV) Acetate in MeOH,4a or by reaction of Benzenesulfinyl Chloride (or p-toluenesulfinyl chloride) with MeOH.4b

Analysis of Reagent Purity: (1) NMR,5a IR,5b UV.5b (2) NMR,5a IR,5c UV.5d

Handling, Storage, and Precautions: these compounds are reported to produce extreme and prolonged burning sensations on contact with the skin.

Preparation of Sulfinyl Compounds.

Methyl arenesulfinates react with compounds containing activated methylene groups, such as ketones6 and sulfones,7 in the presence of Sodium Hydride in DME or Et2O to form a-arylsulfinyl compounds; arylsulfinyl chlorides react similarly (see Benzenesulfinyl Chloride). These sulfinyl-activated compounds are useful synthetic intermediates since they can undergo further reaction;8 the sulfinyl group can then be removed by reductive cleavage with agents such as Aluminum Amalgam, Li(Hg), or Raney Nickel.9 Alternatively, the sulfoxide group may be removed via b-hydrogen elimination either by thermolysis (ca. 80 °C) (eq 1),10,11 or by treatment with base (e.g. RO-, CO32-) with concomitant formation of a double bond.11 Because of the mildness of the procedure, this is one of the better methods for the conversion of ketones, aldehydes, and esters into their a,b-unsaturated derivatives.12

Sulfinylation of a series of lactams by methyl benzenesulfinate is superior to sulfenylation with diphenyl disulfide followed by oxidation; substantial bissulfenylation occurs using the latter procedure.13

Methyl benzenesulfinate has been used to prepare unsaturated sulfoxides via reaction with functionalized unsaturated Grignard reagents,14 and by reaction with phosphonates to form a-phosphoryl sulfoxides that, in turn, form vinyl sulfoxides by Horner-Emmons reactions with aldehydes and ketones.15 These unsaturated sulfinyl compounds undergo a variety of synthetically useful reactions such as cycloadditions,16 Michael additions,17 and various rearrangements.18,19

p-Tolylsulfinylmethyl phenyl sulfone, available from methyl p-toluenesulfinate and Methyl Phenyl Sulfone, reacts with aldehydes and some ketones to form vinyl sulfoxides; these sulfoxides afford g-hydroxy-a,b-unsaturated sulfones after alkene isomerization and rearrangement (eq 2).7

Asymmetric Synthesis.

Although chiral sulfoxides have been prepared in high yield and enantiomeric purity via reaction of optically active p-MeC6H4S(O)OMe with silyl enol ethers,20 a more common procedure has been through reaction of a Grignard reagent or metalated substrate with menthyl p-toluenesulfinate (MenTs).3 Methyl p-toluenesulfinate has been used to prepare menthyl p-toluenesulfinates,21 which are very useful chiral sulfinyl-transfer reagents; the resulting chiral sulfoxides have been used widely in asymmetric synthesis22 (see Benzenesulfinyl Chloride and (-)-(1R,2S,5R)-Menthyl (S)-p-Toluenesulfinate). For example, MenTs has been used to generate b-hydroxy carboxylic esters in high optical yields (eq 3).23

1. For a general review of the preparation and synthetic uses of sulfinic esters, see: The Chemistry of Sulphinic Acids, Esters, and Their Derivatives; Patai, S., Ed.; Wiley: Chichester, 1990.
2. Drabowicz, J.; Kielbasinski, P.; Mikolajczyk, M. In Ref. 1, pp 351-430.
3. Solladié, G. S 1981, 185.
4. (a) Field, L.; Locke, J. M. OSC 1973, 5, 723. (b) Wilt, J. W.; Stein, R. G.; Wagner, W. J. JOC 1967, 32, 2097. See also: Srivastava, P. K.; Field, L. PS 1985, 25, 161 (and references cited therein) for additional methods.
5. (a) Dahn, H.; Toan, V. V.; Ung-Truong, M.-N. MRC 1991, 29, 897. (b) Detoni, S.; Had&zbreve;i, D. JCS 1955, 3163. (c) Tanaka, Y.; Sugimura, T.; Tanaka, Y. CPB 1965, 13, 1384. (d) Bredereck, H.; Brod, G.; Höschele, G. CB 1955, 88, 438.
6. Monteiro, H. J.; De Souza, J. P. TL 1975, 921.
7. Dominguez, E.; Carretero, J. C. TL 1990, 31, 2487.
8. (a) Drabowicz, J.; Kielbasinski, P.; Mikolajczyk, M. In The Chemistry of Sulphones and Sulphoxides; Patai, S.; Rappoport, Z.; Stirling, C., Eds.; Wiley: Chichester, 1988; pp 233-378. (b) Oae, S.; Uchida, Y. In Ref. 8a, pp 583-664. (c) Field, L. S 1978, 713; 1972, 101.
9. Belen'kii, L. I. In Chemistry of Organosulfur Compounds: General Problems; Belen'kii, L. I., Ed.; Horwood: Chichester, 1990; pp 193-228.
10. Cory, R. M.; Chan, D. M. T.; Naguib, Y. M. A.; Rastall, M. H.; Renneboog, R. M. JOC 1980, 45, 1852.
11. Trost, B. M. CRV 1978, 78, 363.
12. March, J. Advanced Organic Chemistry, 3rd ed.; Wiley: New York, 1985; p 913-914.
13. Zoretic, P. A.; Soja, P.; Sinha, N. D. JOC 1978, 43, 1379.
14. Duboudin, J.-G.; Jousseaume, B.; Thoumazeau, E. BSF(2) 1983, 2, 105.
15. Theobald, P. G.; Okamura, W. H. JOC 1990, 55, 741.
16. De Lucchi, O.; Pasquato, L. T 1988, 44, 6755.
17. Posner, G. H. Stud. Org. Chem. (Amsterdam) 1987, 28, 145.
18. Cass, Q. B.; Jaxa-Chamiec, A. A.; Kunec, E. K.; Sammes, P. G. JCS(P1) 1991, 2683.
19. (a) Braverman, S. In The Chemistry of Sulphones and Sulphoxides; Patai, S.; Rappoport, Z.; Stirling, C., Eds.; Wiley: Chichester, 1988; pp 717-758. (b) De Lucchi, O.; Miotti, U.; Modena, G. OR 1991, 40, 157. (c) Satoh, T.; Motohashi, S.; Kimura, S.; Tokutake, N.; Yamakawa, K. TL 1993, 34, 4823.
20. Hiroi, K.; Matsuyama, N. CL 1986, 65 and references therein.
21. Both (R) and (S) forms of menthyl p-toluenesulfinate now are commercially available.
22. (a) Posner, G. H. In The Chemistry of Sulphones and Sulphoxides; Patai, S.; Rappoport, Z.; Stirling, C., Eds.; Wiley: Chichester, 1988; pp 823-850. (b) Cinquini, M.; Cozzi, F.; Montanari, F. Stud. Org. Chem. (Amsterdam) 1985, 19, 355.
23. Mioskowski, C.; Solladié, G. T 1980, 36, 227.

Jeffrey D. Macke

Miles, Kansas City, MO, USA

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