Kinetic diastereoselection of homoallylic indium alkoxides: Syn crotylation of arylaldehydes

Synlett

Volumn , Issue 8, 1998, Pages 903-905

  Lloyd Jones, Guy C ^a   Russell, Tim ^a  

^a UNIVERSITY OF BRISTOL   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 6744239422     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1998-1804     Document Type: Article

References (21)

1. Barbier type allylation refers to reactions in which the carbonyl, metal and allylic halide are reacted simultaneously. This may proceed via formation of radical ion pairs rather than via genuine allylmetal species. T. H. Chan, C. J. Li, M. C. Lee, Z. Y. Wei, Can. J. Chem., 1994, 72, 1181-1192.
2. For leading recent references see: M. B. Isaac, L. A. Paquette, J. Org. Chem., 1997, 62, 5333-5338;
3. see also X.-H. Yi, Y. Meng. C.-J. Li, Tetrahedron Lett., 1997, 38, 4731-4734;
4. T.-P. Loh, X. R. Li, Angew. Chem., Int. Ed. Engl., 1997, 36, 980-982.
5. For reviews see: C.-J. Li, Tetrahedron, 1996, 52, 5643-68;
6. C.-J. Li, idem, Chem. Rev., 1993, 93, 2023-35;
7. P. Cintas, Synlett, 1995, 1087-1096.
8. a) M. B. Isaac, T. H. Chan, Tetrahedron Lett., 1995, 36, 8957-8960;
9. b) S.-C. H. Diana, K.-Y. Sim, T.-P. Loh, Synlett, 1996, 263-264;
10. c) T. H. Chan, M. B. Isaac, Pure & Appl. Chem., 1996, 68, 919-924.
11. X.-R. Li, T.-P. Loh, Tetrahedron: Asymmetry, 1996, 7, 1535-1538.
12. S. Araki, H. Ito, N. Katsumara, Y. Butsugan, J. Organometal. Chem., 1989, 369, 291-296.
13. S. Araki, H. Ito, Y. Butsugan, J. Org. Chem., 1988, 53, 1831-33.
14. S. M. Capps, G. C. Lloyd-Jones, M. Murray, T. M. Peakman, K. E. Walsh; Tetrahedron Lett., 1998 39, 2853-2856;
15. H. A. F. Höppe, G. C. Lloyd-Jones, M. Murray, T. M. Peakman, K. E. Walsh; Angew. Chem., Int. Ed. 1998, 110, 1545.
16. M. T. Reetz, H. Haning, J. Organometal. Chem., 1998, 541, 117-120.
17. For tetraorganoindates see: S. Araki, S.-J. Jin, Y. Butsugan, J. Chem, Soc., Perkin Trans. I, 1995, 549-552.
18. We are currently trying to ascertain what the decomposition products are. We note that the major rotamer of the benzyl-allylic C-C bond in the anti intermediate is likely to be that in which the internal alkenyl carbon is antiperiplanar to the C-OIn bond - decomposition may involve cyclopropyl type intermediates - see ref 7. Also excess crotyl bromide and indium is necessary. As noted, the rate of decomposition of syn-1a may be kinetically linked to anti-1a. A much more detailed kinetic investigation is in progress and will be reported in full in due course.
19. -1, M. Schlosser, J. Hartmann, J. Am. Chem. Soc., 1976, 98, 4674-4676). However, due to low polarisation of the C-In bond E-crotylindium is expected to be favoured and would afford anti-crotylation products on reaction with arylaldehydes via Zimmermann-Traxler type transition states. We suggest that the crotylations discussed here occur through open transition states for which the syn product is expected.
20. 3 solution (syn, 5.5, 5.7 and 5.4 Hz; anti, 7.9, 8.1 and 7.7 Hz respectively). 2-Methyl-1-phenylbut-3-en-l-ol 2a and 2-methyl-1-(p-methoxyphenyl)but-3-en-1-ol 2b are known compounds (2a, U. Schöllkopf, K. Fellenberger, M. Rizk, Liebigs Ann. Chem., 1970, 734, 106-115;
21. 16O, 212.29, requires C, 84.87; H, 7.60 %; found C, 84.50; H 7.94 %.