Catalytic asymmetric ring opening of 2,3-substituted norbornenes with organometallic reagents: A new formal aza functionalization of cyclopentadiene

Organic Letters

Volumn 7, Issue 17, 2005, Pages 3605-3607

  Pineschi, Mauro ^a   Del Moro, Federica ^a   Crotti, Paolo ^a   Macchia, Franco ^a  

^a UNIVERSITY OF PISA   (Italy)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 24044455354     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol050895q     Document Type: Article

References (30)

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16. 2. However, the reaction is not completely regio-and stereoselective, and the main product, racemic anti-1,2-hydroxamic acids of type 4 (through path a, Scheme 2), were invariably obtained in a mixture of ring-opened products of types 5 and 6 in which the attack of the organometallic reagent had occurred at the bridgehead carbon atom (path b, Scheme 2). See: Surman, M. D.; Mulvihill, M. J.; Miller, M. J. J. Org. Chem. 2002, 67, 4115-4121.
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19. (b) Pineschi, M.; Del Moro, F.; Gini, F.; Minnaard, A. J.; Feringa, B. L. Chem. Commun. 2004, 1244-1245.
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25. On the other hand, trialkylaluminums gave a complex mixture of products when used with oxabicyclic compounds 1a,b and with bicyclic hydrazine 2a.
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27. Some other phosphoramidite ligands that were employed gave lower enantioselectivities (see Supporting Information).
28. 3 proved to be only scarcely reactive in our reaction conditions (<10% conversion after 18 h at 0°C, data not reported in Table 2).
29. Fraser, P. K.; Woodward, S. Chem. Eur. J. 2003, 9, 776-782.
30. Reactions reported in Table 2 can be performed at -25°C for 10-18 h with only marginal variation of ee values.