1,3,2-Dioxathiolane 2,2-Dioxide1

(R1 = R2 = H)

[1072-53-3]  · C2H4O4S  · 1,3,2-Dioxathiolane 2,2-Dioxide  · (MW 124.13) (R1 = R2 = n-Bu)

[127901-92-3]  · C10H20O4S  · 4,5-Dibutyl-1,3,2-Dioxathiolane 2,2-Dioxide  · (MW 236.37)

(display epoxide-like reactivity;2,3 nucleophilic displacement of both oxygen functions is feasible4-6)

Alternate Names: ethylene sulfate; cyclic sulfates.

Preparative Methods: cyclic sulfates of 1,2-diols (1,3,2-dioxathiolane 2,2-dioxides) are most easily prepared in a two-step procedure (eq 1).2 Reaction of a 1,2-diol with Thionyl Chloride leads to a cyclic sulfite which is then oxidized to the corresponding cyclic sulfate (1). Direct conversion of a 1,2-diol to a cyclic sulfate using Sulfuryl Chloride is generally less efficient.2,3

Handling, Storage, and Precautions: the structural similarity between cyclic sulfates and Dimethyl Sulfate must be recognized. Dimethyl sulfate, and to a lesser extent ethylene sulfate, are carcinogenic and potent alkylating agents that are toxic by inhalation and ingestion.1 Cyclic sulfates must, as a result, be treated with extreme care.

Cyclic sulfates of 1,2-diols are an important group of reagents and recent advances in the asymmetric dihydroxylation of alkenes (see Osmium Tetroxide) will serve to increase further their synthetic potential.7 Cyclic sulfates display reactivity towards nucleophiles that is closely related to that of epoxides and react in a regioselective fashion with hydride (eq 2)2 and a wide range of heteroatoms (eqs 3-5)2,3,8,9 and carbon-based nucleophiles (eq 6).2,5,6

The reactivity of nitrogen nucleophiles towards cyclic sulfates has attracted considerable interest and provides an efficient entry into 1,2-amino alcohols (eq 7).4,10

It is, however, important to appreciate the additional scope offered by cyclic sulfates over epoxides as electrophilic components in displacement processes. Following nucleophilic ring-opening, the intermediate b-sulfate, e.g. (2), functions as a leaving group and can undergo a second displacement.2 This provides a direct access to aziridines (including N-unsubstituted variants) (eq 8),4,10 to 1,2-diamines (eq 9),11 and, with activated carbon nucleophiles, to cyclopropanes (eq 10).5,6

In cyclic sulfates derived from a,b-unsaturated esters, regioselective nucleophilic attack has been observed (eq 11);2 the corresponding epoxide undergoes ring opening with a lower level of regioselectivity.

Cyclic sulfates are stable towards L-selectride (Lithium Tri-s-butylborohydride)12 and are also compatible with acid (and the sulfate cleaved in the presence of acid-labile protecting groups, e.g. OTBDMS, acetonide).13

1.Lohray, B. B. S 1992, 1035.
2. Gao, Y.; Sharpless, K. B. JACS 1988, 110, 7538.
3. Berridge, M. S.; Franceschini, M. P.; Rosenfeld, E.; Tewson, T. J. JOC 1990, 55, 1211.
4. (a) Metz, K.; Honda, M.; Komori, T. LA 1993, 55. (b) Lohray, B. B.; Ahuja, J. R. CC 1991, 95. (c) Barrett, A. G. M.; Sakadarat, S. JOC 1990, 55, 5110.
5. Ramaswany, S.; Prasad, K.; Repič, O. JOC 1992, 57, 6344.
6. Bryson, T. A.; Koen, J. H.; Roth, G. A. SL 1992, 723.
7. (a) Amberg, W.; Bennani, Y. L.; Chadha, R. K.; Crispino, G. A.; Davis, W. D.; Hartung, J.; Jeong, K-S.; Ogino, Y.; Shibata, T.; Sharpless, K. B. JOC 1993, 58, 844. (b) Lohray, B. B. TA 1992, 3, 1317.
8.Matsumiya, S.; Izuoka, A.; Sugawara, T.; Taruishi, T.; Kawada, Y. BCJ 1993, 66, 513.
9. Takano, S.; Yanase, M.; Ogasawara, K. CL 1989, 1689.
10. Lohray, B. B.; Gao, Y.; Sharpless, K. B. TL 1989, 30, 2623.
11. Oi, R.; Sharpless, K. B. TL 1991, 32, 999.
12. Wang, W.-B.; Roskamp, E. J. TL 1992, 33, 7631.
13. Kim, B. M.; Sharpless, K. B. TL 1989, 30, 655.

Nicholas J. Lynch

University of Bristol, UK

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