Tetrahedron

Controlling 6-endo-selectivity in oxidation/bromocyclization cascades for synthesis of aplysiapyranoids and other 2, 2, 6, 6-substituted tetrahydropyrans

…, U Bergsträßer, H Kelm, J Hartung, M Greb, I Svoboda…

文献索引：Bruecher, Oliver; Bergstraesser, Uwe; Kelm, Harald; Hartung, Jens; Greb, Marco; Svoboda, Ingrid; Fuess, Hartmut Tetrahedron, 2012 , vol. 68, # 34 p. 6968 - 6980

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被引用次数: 7

摘要

A cascade, composed of (i) oxovanadium (V)-catalyzed oxidation of bromide by tert-butyl hydroperoxide and (ii) stereoselective 6-endo-bromocyclization, affords 3-bromo-2-aryl-2, 6, 6-trimethyltetrahydropyrans from styrene-type tertiary alkenols in synthetically useful yields.(E)-Alkenols add the bromo-and the alkoxy substituent anti-selectively across the double bond, indicating a bromonium ion-mechanism for the ring closure. 6-endo-control ...