Synthesis 1997; 1997(9): 1041-1044
DOI: 10.1055/s-1997-1315
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Regiospecific Control of Additions of 4-Substituted 3,5-Dimethylisoxazoles to α,β Unsaturated Carbonyls

J. R. Stenzel
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Publication History

Publication Date:
31 December 2000 (online)

Transmetalation of C-5-lithiomethylisoxazoles with the lower-order cuprate reagent lithium thienylcyanocuprate (Li[ThCuCN]) in THF results in exclusive conjugate addition to α,β-unsaturated carbonyls. In contrast, transmetalation with samarium tris(hexamethyldisilazide) (Sm[HMDS]3) in diethyl ether directs 1,2-carbonyl addition. In both cases, optimum results were realized with a 4,5-dihydro-4,4-dimethyl-Δ 2-oxazoline substituent at the C-4 position of the isoxazole.

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