Calcium Carbonate

CaCO3

[471-34-1]  · CCaO3  · Calcium Carbonate  · (MW 100.09)

(relatively insoluble white solid; a useful acid scavenger and stabilizing agent for acid sensitive compounds,1 and a coreactant in reactions producing acidic byproducts.)

Physical Data: widely available as powder (reagent grade) or ppt powder (USP). Occurs naturally as limestone, marble, and chalk. Three crystal forms are known: (1) aragonite [14791-73-2]; mp 825 °C (dec); d 2.93 g cm-3; water sol 0.0015 g/100 mL (at 25 °C); (2) calcite [13397-26-7]; mp 1339 °C (103 atm); d 2.71 g cm-3; water sol 0.0014 g/100 mL (at 25 °C); (3) vaterite [13701-58-1]; found in N. Ireland and Israel.

Handling, Storage, and Precautions: none; nontoxic; generates calcium oxide and releases carbon dioxide on heating.

Elimination.

Halides (eq 1)2 and sulfoxides (eq 2)3 are converted to alkenes (or their tautomers) on heating with CaCO3 in appropriate solvents. In the case of halo ketone eliminations (eq 3)4 the methods of Holysz5a and Joly,5b employing lithium carbonate/lithium halide mixtures, appear to be more commonly used, and in some instances more effective (see Lithium Carbonate-Lithium Bromide).6

Halogenation.

Calcium carbonate is often used with reagents such as N-Bromosuccinimide (eq 4),7 phosphorus halides,8 and Benzyltrimethylammonium Dichloroiodate (BTMA) (eq 5).9

Substitutions.

Silver(I) Perchlorate promoted substitutions of reactive halides may be effected under mild conditions, as shown in eq 610 and eq 7.11 This provides a useful alternative12 to classical Friedel-Craft conditions.

Pinacol Rearrangement.

Rearrangement of glycol monotosylates (eq 8)13 is effected by the procedure of Corey.14 Solvolysis of an analogous bicyclic epoxy tosylate in an aqueous suspension of CaCO3 gave a 1,5-diketone in good yield (eq 9).15

Thioether and Acetal Deprotection.

Mercury(II) Chloride induced cleavage of thioethers16 and acetals (eq 10),17 and their selenium analogs,18 employs added CaCO3.

Cycloadditions.

Cycloaddition (eq 11)19 and related reactions (eq 12)20 have sometimes used CaCO3 as a coreactant.

Other Divalent-Metal Carbonates.

Other divalent-metal carbonates related to calcium carbonate include MgCO3 [546-93-0], Zinc Carbonate [3486-35-9], SrCO3 [1633-05-2], and BaCO3 [513-77-9]. In general, these carbonates have not been widely used. Barium carbonate has served a similar role in halogenation and dehydrohalogenation reactions as the calcium salt. Since barium is more toxic than calcium, its equivalent use is not recommended. Calcium, strontium, and barium carbonates have all been used as supports for noble metal catalysts in hydrogenation reactions, and in some cases appear to give better selectivity than analogous carbon- or alumina-supported catalysts.21

A novel coumarin synthesis (eq 13), employing zinc or magnesium carbonate,22 avoids the acidic conditions of the Pschorr synthesis.


1. (a) Campaigne, E.; Tullar, B. F. OSC 1963, 4, 921. (b) Parish, E. J.; Luo, C.; Parish, S.; Heidepriem, R. W. SC 1992, 22, 2839.
2. Cope, A. C.; Clark, J. R.; Connor, R. OSC 1943, 2, 181.
3. Fujisawa, T.; Noda, A.; Kawara, T.; Sato, T. CL 1981, 1159.
4. Green, G. F. H.; Long, A. G. JCS 1961, 2532.
5. (a) Holyz, R. P. JACS 1953, 75, 4432. (b) Joly, R.; Warnant, J.; Nomine, G.; Bertin, D. BSC 1958, 366.
6. Demuth, M. R.; Garrett, P.; White, J. D. JACS 1976, 98, 634.
7. Farina, G.; Zecchi, G. S 1977, 755.
8. Carman, R.; Shaw, I. M. AJC 1976, 29, 133.
9. Kajigaeshi, S.; Kakinami, T.; Yamasaki, H.; Fujisaki, S.; Okamoto, T. BCJ 1988, 61, 600.
10. Shimizu, N.; Watanabe, K.; Tsuno, Y. BCJ 1984, 57, 1165 (cf. general method JACS 1982, 104, 1330).
11. Kral, V.; Arnold, Z. S 1982, 823.
12. Zavada, J.; Pankom, M.; Arnold, Z. CCC 1976, 41, 1777.
13. Mazur, Y.; Nussim, M. JACS 1961, 83, 3911.
14. Corey, E. J.; Ohno, M.; Mitra, R. B.; Vatakencherry, P. A. JACS 1964, 86, 478.
15. Gray, R. W.; Dreiding, A. S. HCA 1977, 60, 1969.
16. Corey, E. J.; Bock, M. G. TL 1975, 2643.
17. Langley, D. R.; Thurston, D. E. JOC 1987, 52, 91.
18. Burton, A.; Hevesi, L.; Dumont, W.; Cravader, A.; Krief, A. S 1979, 877.
19. Manna, S.; Falck, J. R.; Mioskowski, C. JOC 1982, 47, 5021.
20. Tachikawa, R.; Miyadera, T.; Tamura, C; Terada, A.; Naruto, S.; Nagamatsu, E. JCS(P1) 1978, 1524.
21. (a) Augustine, R. L. Catalytic Hydrogenation; Techniques and Applications in Organic Synthesis; Dekker: New York, 1965. (b) Rylander, P. N. Catalytic Hydrogenation over Platinum Metals; Academic Press: New York, 1967.
22. Buchi, G.; Weinreb, S. M. JACS 1971, 93, 746.

William Reusch

Michigan State University, East Lansing, MI, USA



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