[290-13-1]  · C4H6O2  · 4H-1,3-Dioxin  · (MW 86.10)

(precursor to a b-formylvinyl anion equivalent;1 useful for the preparation of b-substituted acroleins,1-3 syn-1,3-diols,4 and anti,anti-1,2,3-triols4)

Physical Data: bp 97-99 °C.

Solubility: sol THF, ether, hexanes.

Preparative Methods: by elimination of 5-tosyloxy-1,3-dioxane in DMSO using Potassium t-Butoxide5 or KOCMe2C6H136 as the base. A more convenient procedure employs triethylene glycol as the solvent and Potassium Hydroxide as the base.2

Handling, Storage, and Precautions: thermally labile. A rapid distillation is required in order to prevent decomposition via retrocycloaddition to acrolein and formaldehyde.

b-Formylvinyl Anion Equivalent.

4H-1,3-Dioxin undergoes rapid metalation upon treatment with s-Butyllithium or t-Butyllithium to provide the allylic anion (1).1 A variety of electrophiles such as alkyl halides, epoxides, aldehydes, and ketones can be employed in subsequent alkylation reactions to afford 4-substituted dioxins which smoothly undergo bis-hetero retrocycloaddition reactions upon refluxing in toluene (4-12 h) to provide (E)-a,b-unsaturated aldehydes, presumably through a boat-like transition state with the alkyl substituent in a pseudoequatorial position (eq 1).1 Moreover, the thermal generation of b-substituted acroleins has been exploited in a one-pot retrocycloaddition-cycloaddition sequence (eq 2).1

Numerous b-formylvinyl anion equivalents have been previously reported. However, the use of all of these equivalents requires at least one reagent-mediated step to unravel the a,b-unsaturated aldehyde after the alkylation step, e.g.: (2) HgCl2, MeCN, H2O, 50 °C;7 (3) H2O2;8 (4) H3O+;9 (5) H3O+;10 (6) 1 H3O+, 2 NEt3;11 and (7) 1 Pt, e-, 2 NEt3.12

syn-1,3-Dihydroxy- and anti,anti-1,2,3-Trihydroxypropanediyl 1,3-Dianion Equivalents.

4-Alkyl-1,3-dioxins, such as the one shown in eq 1, can be further metalated and alkylated with excellent regioselectivity to provide 4,6-dialkyl-1,3-dioxins (eq 3). Hydroboration reactions of 4,6-dialkyl-1,3-dioxins proceed with complete stereoselectivity from the face opposite the 6-alkyl substituent to provide, after oxidative workup, a single 5-hydroxy-substituted dioxin which can be hydrolyzed to an anti,anti-1,2,3-triol (eq 4). Excellent diastereofacial discrimination is similarly observed in the hydrogenation reactions of 4,6-dialkyl-1,3-dioxins to provide only a syn-1,3-diol after hydrolysis (eq 5).

b-Formylvinyl Cation Equivalent.

4H-1,3-Dioxin participates in Heck reactions with a variety of aryl halides and aryl triflates to afford 4-aryl-substituted dioxins which, upon thermolysis in refluxing toluene, are transformed to 3-arylacroleins (eq 6).3

Related Reagents.


1. Funk, R. L.; Bolton, G. L. JACS 1988, 110, 1290.
2. Grothe, U.; Schöllkopf, U.; Tiller, T. T 1991, 47, 2835.
3. Sakamoto, T.; Kondo, Y.; Yamanaka, H. TL 1992, 33, 6845.
4. Funk, R. L.; Bolton, G. L. TL 1988, 29, 1111.
5. Camerlynck, R.; Anteunis, M. T 1975, 31, 1837.
6. Bolton, G. L. Doctoral Dissertation, Univ. of Nebraska, 1988, 188.
7. (a) Corey, E. J.; Erickson, B. W.; Noyori, R. JACS 1971, 93, 1724. (b) For the related 3-methylthio-1-sodio-2-propenyl p-tolyl sulfone, see: Ogura, K.; Iihama, T.; Takahashi, K; Iida, H. TL 1984, 25, 2671.
8. (a) Reich, H. J.; Clark, M. C.; Willis, W. W., Jr. JOC 1982, 47, 1618. (b) For the related 1,3-dilithio-2-propynyl phenyl selenide, see: Reich, H. J.; Shah, S. K.; Gold, P. M.; Olson, R. E. JACS 1981, 103, 3112.
9. Meyers, A. I.; Spohn, R. F. JOC 1985, 50, 4872.
10. (a) Clinet, J.-C.; Linstrumelle, G. TL 1978, 1137. (b) For the related 3-lithio-1-methoxy-1,2-propadienyltrimethylsilane, see: Clinet, J.-C.; Linstrumelle, G. TL 1980, 21, 3987.
11. (a) Kondo, K.; Tunemoto, D. TL 1975, 1007. (b) Julia, M.; Badet, B. BSF(2) 1975, 1363.
12. (a) Cristau, H. J.; Chabaud, B.; Niangoran, C. JOC 1983, 48, 1527. (b) For the related (3,3-diisopropoxypropyl)triphenylarsonium ylide, see: Chabert, P.; Ousset, J. B.; Mioskowski, C. TL 1989, 30, 179.

Raymond L. Funk

Pennsylvania State University, University Park, PA, USA

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