(E)-3-Tri-n-butylstannyl-2-propenyl 2-Tetrahydropyranyl Ether1

[55723-10-9]  · C20H40O2Sn  · (E)-3-Tri-n-butylstannyl-2-propenyl 2-Tetrahydropyranyl Ether  · (MW 431.31)

(efficiently transmetalated by alkyllithium reagents;2 palladium-catalyzed coupling affords substituted allylic alcohols)

Physical Data: bp 140-142 °C/0.1 mmHg;2 1H NMR data have been reported.4

Solubility: sol THF, DMF.

Preparative Method: hydrostannation of propargyl tetrahydropyranyl ether affords the (Z)-isomer [87830-21-5], which isomerizes at temperatures above 80 °C.2,3

Purification: can be purified by distillation.2,3

Handling, Storage, and Precautions: organostannane reagents are potentially toxic. Therefore their preparation and use must be conducted wearing appropriate protective clothing and in a well-ventilated hood. The reagent should be stored under an inert atmosphere and protected from light.

Transmetalation.

Alkyllithium reagents efficiently transmetalate (E)-3-tributylstannyl-2-propenyl 2-tetrahydropyranyl ether (1) to afford (E)-3-lithiopropenyl 2-tetrahydropyranyl ether, which exhibits reactivity typical of vinyllithium reagents.2

Cross-Coupling Reactions.

Stille et al. pioneered the palladium-catalyzed cross-coupling reaction of organostannanes with a variety of electrophilic partners. These reactions proceed under mild conditions, which are often compatible with typically sensitive functional groups.1 Palladium-catalyzed couplings of (1) with vinyl halides (eq 1)5 and heteroaryl halides (eq 2)6 have been reported. Coupling of (1) (7:1 E/Z ratio) with aromatic triflates affords a 3:1 mixture of alkenic products (eq 3).7a Isomerically pure allylic alcohols can be obtained directly from the palladium-catalyzed coupling of (E)- and (Z)-1-(tributylstannyl)-1-propen-3-ol with aromatic triflates.7a

Aromatic triflates7b and allylic halides8 couple with (1) in the presence of carbon monoxide to afford the corresponding a,b-unsaturated ketones (eq 4).7b

Coupling of (1) (1:1 E/Z ratio) with sulfonyl chlorides affords the corresponding isomerically pure (E)-allylic sulfone in good yield (eq 5).9 Presumably, a mixture of allylic sulfones is formed initially which subsequently isomerizes under the reaction conditions to provide the thermodynamically more stable (E)-isomer. Similar isomerizations are observed in the palladium-catalyzed coupling of acid chlorides with (Z)-vinylstannanes.10


1. For recent reviews and collected papers on the chemistry of organostannanes, see: (a) Mitchell, T. N. S 1992, 803. (b) Pereyre, M.; Quintard, J. R.; Rhan, A. Tin in Organic Synthesis; Butterworths: London, 1987. (c) Yamamoto, Y. Organo Tin Compounds in Organic Synthesis; T 1989, 45. (d) Chemistry of Tin; Harrison, P. G., Ed.; Chapman and Hall: New York, 1989. (e) Stille, J. K. AG(E) 1986, 25, 508.
2. Corey, E. J.; Wollenberg, R. H. JOC 1975, 40, 2265.
3. Corey, E. J.; Suggs, J. W. JOC 1975, 40, 2554.
4. Zhang, H. X.; Guibé, F.; Balavoine, G. JOC 1990, 55, 1857.
5. (a) Stille, J. K.; Sweet, M. P. TL 1989, 30, 3645. (b) Férézou, J. P.; Julia, M.; Li, Y.; Liu, W.; Pancrazi, A. SL 1991, 53.
6. (a) Crisp, G. T. SC 1989, 19, 2117. (b) Solberg, J.; Undheim, K. ACS(B) 1987, 712.
7. (a) Echavarren, A. M.; Stille, J. K. JACS 1987, 109, 5478. (b) Echavarren, A. M.; Stille, J. K. JACS 1988, 110, 1557.
8. (a) Sheffy, F. K.; Godschalx, J. P.; Stille, J. K. JACS 1984, 106, 4833. (b) Sheffy, F. K.; Stille, J. K. JACS 1983, 105, 7173.
9. Labadie, S. S. JOC 1989, 54, 2496.
10. Labadie, J. W.; Stille, J. K. JACS 1983, 105, 6129.

Alfred P. Spada

Rhône-Poulenc Rorer Central Research, Collegeville, PA, USA



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