Biomimetic epoxide-opening cascades of polyepoxides enable the efficient and rapid construction of polyether frameworks.H erein, we show that the epoxide-opening cascade cyclization that affords tetrahydrofuran products in acidic aqueous media produces tetrahydropyran (THP) in neutral water.T HP formation proceeded by simply heating polyepoxides in neutral water and followed ad ifferent cyclization mode from those observed so far.T he novel cascade cyclization in H 2 Ow as applied to the synthesis of an ew nerolidol-type sesquiterpenoid, resulting in revision of the proposed structure and determination of the absolute configuration.Scheme 2. endo-Selectivee poxide-opening cascade in H 2 Oreported by Jamison et al [9a] (A)and this work (B).

No abstract

Biomimetic epoxide‐opening cascades of polyepoxides enable the efficient and rapid construction of polyether frameworks. Herein, we show that the epoxide‐opening cascade cyclization that affords tetrahydrofuran products in acidic aqueous media produces tetrahydropyran (THP) in neutral water. THP formation proceeded by simply heating polyepoxides in neutral water and followed a different cyclization mode from those observed so far. The novel cascade cyclization in H2O was applied to the synthesis of a new nerolidol‐type sesquiterpenoid, resulting in revision of the proposed structure and determination of the absolute configuration.

Eine Cyclisierungskaskade durch Ringöffnung von Polyepoxiden führt in saurem wässrigem Medium zu Tetrahydrofuran(THF)‐, in neutralem Wasser hingegen zu Tetrahydropyran(THP)‐Ringen. Y. Morimoto und Mitarbeiter beschreiben diesen Wechsel in ihrer Zuschrift auf S. 10274. Im Titelbild steht eine Schienenweiche für diesen divergierenden Verlauf der Polyepoxid‐Cyclisierung, wobei der rechte Waggon die THP‐Bildung beim Erhitzen in neutralem Wasser darstellt.

The epoxide‐opening cascade cyclization of polyepoxides, which produces tetrahydrofuran (THF) in acidic aqueous media, produces tetrahydropyran (THP) in neutral water, as shown by K. Nishikawa, Y. Morimoto, and co‐workers in their Communication on page 10168 ff. A railway junction is used to illustrate the switching of polyepoxide cyclization modes. The trolley splash on the right side represents the formation of THP by heating polyepoxides in neutral water.