Total syntheses of the squalene-derived halogenated polyethers ent -dioxepandehydrothyrsiferol and armatol A via bromonium- and Lewis acid-initiated epoxide-opening cascades
نویسندگان
چکیده
منابع مشابه
Total syntheses of the squalene-derived halogenated polyethers ent-dioxepandehydrothyrsiferol and armatol A via bromonium- and Lewis acid-initiated epoxide-opening cascades.
Herein we describe in full our investigations leading to the first total syntheses of ent-dioxepandehydrothyrsiferol and armatol A. Discovery of a bromonium-initiated epoxide-opening cascade enabled novel tactics for constructing key fragments found in both natural products and have led us to revise the proposed biogeneses. Other common features found in the routes include convergent fragment c...
متن کاملTotal synthesis of ent-dioxepandehydrothyrsiferol via a bromonium-initiated epoxide-opening cascade.
In the first total synthesis of ent-dioxepandehydrothyrsiferol, the signature trans-anti-trans 7,7,6-fused tricyclic polyether framework was constructed in a single bromonium-initiated epoxide-opening cascade that incorporates both endo- and exo-selective epoxide openings, each directed by the substitution pattern of the epoxide (methyl groups). This study thus demonstrates the feasibility of a...
متن کاملSynthesis of Marine Polycyclic Polyethers via Endo-Selective Epoxide-Opening Cascades
The proposed biosynthetic pathways to ladder polyethers of polyketide origin and oxasqualenoids of terpenoid origin share a dramatic epoxide-opening cascade as a key step. Polycyclic structures generated in these biosynthetic pathways display biological effects ranging from potentially therapeutic properties to extreme lethality. Much of the structural complexity of ladder polyether and oxasqua...
متن کاملthe investigation of the relationship between type a and type b personalities and quality of translation
چکیده ندارد.
Epoxide-opening cascades promoted by water.
Selectivity rules in organic chemistry have been inferred largely from nonaqueous environments. In contrast, enzymes operate in water, and the chemical effect of the medium change remains only partially understood. Structural characterization of the "ladder" polyether marine natural products raised a puzzle that persisted for 20 years: Although the stereochemistry of adjacent tetrahydropyran (T...
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ژورنال
عنوان ژورنال: Tetrahedron
سال: 2013
ISSN: 0040-4020
DOI: 10.1016/j.tet.2013.04.041