- Rhodium(II)-Catalyzed One-Pot Four-Component Synthesis of Functionalized Polyether Macrocycles at High Concentration
Walid Zeghida, Céline Besnard, Jérôme Lacour
Angew. Chem. Int. Ed. 2010, 49, 7253-7256
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Against conventional wisdom, the rhodium(II)-catalyzed nontemplated macrocyclization of four separate components in one reaction vessel became more efficient as the concentration was increased. Thus, α-diazo-β-ketoesters underwent condensation with 1,4-dioxane, tetrahydrofuran, or tetrahydropyran as the solvent to yield 16- to 18-membered polyether macrocycles in up to 75 % yield (see scheme; R=Me, Et, PhCH2CH2, allyl, PhCHCH2).
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