Lithiated benzyllithiums from chlorobenzyl chlorides by a DTBB-catalysed lithiation

Tetrahedron Letters

Volumn 38, Issue 4, 1997, Pages 687-690

  Gómez, Cecilia ^a   Huerta, Fernando F ^a   Yus, Miguel ^a  

^a UNIVERSITY OF ALICANTE   (Spain)

Author keywords

[No Author keywords available]

Indexed keywords

ORGANOLITHIUM COMPOUND;

ARTICLE; CATALYSIS; CHEMICAL REACTION; DRUG SYNTHESIS; STEREOCHEMISTRY;

EID: 0242385001     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(96)02393-3     Document Type: Article

References (19)

1. See, for instance: Wakefield, B. J. Organolithium Methods; Academic Press: London, 1988.
2. Akiyama, S.; Hooz, J. Tetrahedron Lett. 1973, 4115-4118.
3. Schlenk, W.; Holtz, J. Ber. Dtsch. Chem. Ger. 1917, 50, 262-274; Chem. Abstr. 1917, 11, 2796.
4. Schlenk, W.; Holtz, J. Ber. Dtsch. Chem. Ger. 1917, 50, 262-274; Chem. Abstr. 1917, 11, 2796.
5. Guijarro, D.; Mancheño, B.; Yus, M. Tetrahedron 1992, 48, 4593-4600.
6. For a monograph see: Blomberg, C. The Barbier Reaction and Related One-step Process; Springer-Verlag: Berlin, 1993.
7. (a) Reference 5, p. 79.
8. (b) Reference 5, p. 83.
9. (c) Alternatively benzyl methyl ether can be used as starting material to generate benzyllithium under Barbier-type reaction conditions: reference 5, p. 79.
10. (d) For a recent paper on the use of 2-bromobenzyl bromide for benzyl coupling by bromine/lithium exchange, see: Warren, S.; Wyatt, P.; McPartlin, M.; Woodroffe, T. Tetrahedron Lett. 1996, 37, 5609-5612.
11. (a) For the first account on this reaction, see: Yus, M.; Ramón, D. J. J. Chem. Soc., Chem. Commun. 1991, 398-400.
12. (b) For a recent review, see: Yus, M., Chem. Soc. Rev. 1996, 155-161.
13. For the last paper on this topic from our laboratory, see: Bachki, A.; Foubelo, F.; Yus, M., Tetrahedron: Asymmetry 1996, 7, 2997-3008.
14. For the last paper on this topic from our laboratory, see: Almena, J.; Foubelo, F.; Yus, M., Tetrahedron 1996, 52, 8545-8564.
15. For a review, see: Najera, C.; Yus, M. Trends Org. Chem. 1991, 2, 155-181.
16. For the last paper on this topic from our laboratory, see: Ramón, D. J.; Yus, M., Tetrahedron 1996, 52, 13739-13750.
17. For the last paper on this topic from our laboratory, see: Guijarro, A.; Yus, M., Tetrahedron 1996, 52, 1797-1810.
18. As a comparison, surprisingly the same process carried out in absence of the arene catalyst also works giving the expected product in even better yields (>90%). One possible explanation for this apparently strange behaviour could be that the starting material (benzyl chloride), the reaction product (1-benzylcyclohexanol) or other aromatic species generated during the reaction (benzyllithium, 1,2-diphenylethane, ...) could act as electron carrier catalysts. One proof of that would be that during the non-catalysed reaction, after an induction time of ca. 20 min, a slight red-brown colour is developed, which is, in general, typical whenfor radical-anion species are generatedin this type of processes. We thank the referee for calling our attention on a justification for the non-catalysed reaction.
19. Under these reaction conditions (-50°C) the nuclear chlorine/lithium exchange works very slowly so, for short reaction times (ca. 20 min), no aromatic lithiation was observed. For the two-step process we never found reaction products in which the electrophile is attached to the aromatic ring.