3,3-Diethoxy-1-propyne

(R = H)

[10160-87-9]  · C7H12O2  · 3,3-Diethoxy-1-propyne  · (MW 128.17) (R = Li)

[51756-42-4]  · C7H11LiO2  · 3,3-Diethoxy-1-propyne  · (MW 134.10)

(intermediate for the synthesis of unsaturated and polyunsaturated compounds and numerous heterocycles1)

Alternate Names: propiolaldehyde diethyl acetal; propargylaldehyde diethyl acetal.

Physical Data: bp 138-139.5 °C; d 0.894 g cm-3.

Solubility: sol standard organic solvents.

Form Supplied in: colorless liquid; commercially available.

Analysis of Reagent Purity: IR: 3260, 2125 cm-1; 1H NMR (CDCl3): d 1.24 (t, J = 7, 6H), 2.58 (d, J = 2, 1H), 3.71 (q of d, J = 7, 2, 4H), 5.21 (d, J = 2, 1H).

Preparative Methods: the synthesis of this reagent can be accomplished according to eq 1. The dehydrobromination step can be carried out with Potassium Hydroxide in ethanol,2 with Sodium Amide in liquid ammonia,3 or by using Sodium Hydroxide in the presence of a phase transfer agent.1a,4 3,3-Diethoxy-1-propyne can also be prepared according to eq 2.5

The lithio derivative, named (3,3-diethoxy-1-propynyl)lithium, is easily prepared by reaction of 1 equiv of a saturated lithium compound (e.g. n-Butyllithium) with a solution of the acetal in ether or THF.6

Purification: by distillation at reduced pressure, bp 95-96 °C/170 mmHg.1a

Handling, Storage, and Precautions: should be stored in a refrigerator and protected from moisture.

Alkylation Reactions.

Reaction of the lithio derivative with organic halides and carbonyl compounds leads to the synthesis of unsaturated and polyunsaturated acetals and aldehydes.6-8 Alkylation can also be performed by reaction of 3,3-diethoxy-1-propyne with halides (catalyzed by transition metal compounds)9 or by Cadiot-Chodkiewicz coupling.10

Addition Reactions.

Interesting results are obtained by addition of organocuprates to 3,3-diethoxy-1-propyne owing to the regio- and stereoselectivity of the reaction (eq 3).11,12

Recently, the stannocupration of 3,3-diethoxy-1-propyne has been found to lead to a bifunctional adduct, providing a useful synthon for further synthetic elaboration (eq 4).13,14

Heterocycle Synthesis.

The acetal and its lithio derivative have been used in the synthesis of numerous heterocyclic compounds, including furans,8,9a pyrazoles (eq 5),15 isoxazoles,16 and triazoles.2

Some natural products have been synthesized by using 3,3-diethoxy-1-propyne and its lithio derivative as intermediates.12,17-20


1. (a) Le Coq, A.; Gorgues, A. OS 1980, 59, 10. (b) Fieser, L. F.; Fieser, M. FF 1969, 2, 126; FF 1972, 3, 93.
2. Sheehan, J. C.; Robinson, C. A. JACS 1949, 71, 1436.
3. Ward, J. P.; Van Dorp, D. A. RTC 1966, 85, 117.
4. Dehmlow, E. V.; Lissel, M. T 1981, 37, 1653.
5. Barbot, F.; Poncini, L.; Randrianoelina, B.; Miginiac, P. JCR(S) 1981, 343; JCR(M) 1981, 4016.
6. (a) Barbot, F.; Miginiac, P. BSF(2) 1983, 41 (CA 1983, 99, 53 064z). (b) Freskos, J. N.; Morrow, G. W.; Swenton, J. S. JOC 1985, 50, 805.
7. Kiely, J. S.; Boudjouk, P.; Nelson, L. L. JOC 1977, 42, 2626.
8. Obrecht, D. HCA 1989, 72, 447.
9. (a) Arcadi, A.; Marinelli, F. S 1986, 749. (b) Sakamoto, T.; Shiga, F.; Yasuhara, A.; Uchiyama, D.; Kondo, Y.; Yamanaka, H. S 1992, 746.
10. Ward, J. P.; Van Dorp, D. A. RTC 1967, 86, 545.
11. Alexakis, A.; Commerçon, A.; Villiéras, J.; Normant, J. F. TL 1976, 2313 (CA 1977, 86, 5566z).
12. Alexakis, A.; Commerçon, A.; Coulentianos, C.; Normant, J. F. T 1984, 40, 715.
13. Beaudet, I.; Parrain, J. L.; Quintard, J. P. TL 1991, 32, 6333.
14. Marek, I.; Alexakis, A.; Normant, J. F. TL 1991, 32, 6337.
15. Buchanan, J. G.; Quijano, M. L.; Wightman, R. H. JCS(P1) 1992, 1573.
16. Macrides T. A.; Thaller, V. JCR(S) 1981, 156; JCR(M) 1981, 2001.
17. Le Doussal, B.; Le Coq, A.; Gorgues, A.; Meyer, A. T 1983, 39, 2185 (CA 1983, 99, 122 095z).
18. Bütikofer, P. A.; Eugster, C. H. HCA 1983, 66, 1148 (CA 1983, 99, 195 252h).
19. Jones, E. R. H.; Thaller, V.; Turner, J. L. JCS(P1) 1975, 424.
20. Schreiber, S. L.; Kiessling, L. L. JACS 1988, 110, 631.

Francis Y. Barbot

Université de Poitiers, France



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