2008

Isoxazole derivativesR 0240 Hydrazide-Catalyzed 1,3-Dipolar Nitrone Cycloadditions. — The triflate or per-

chlorate salts of chiral camphor-derived hydrazides are highly selective catalysts for the [3 + 2] cycloaddition of nitrones to α,β-unsaturated aldehydes. Although the dia-stereoselectivities are only moderate, exo-adducts are obtained which are otherwise dif-ficult to synthesize from acyclic dipolarophiles. The rigorous control of the water con-tent is necessary to obtain better yields and higher enantioselectivity. — (LEMAY, M.; TRANT, J.; OGILVIE*, W. W.; Tetrahedron 63 (2007) 47, 11644-11655; Dep. Chem., Univ. Ottawa, Ottawa, Ont. K1N 6N5, Can.; Eng.) — Klein

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