A Versatile Synthesis of 3-Substituted 5-Alkyl Butyrolactones Via Dyotropic Rearrangement

Chromium(III) Octaethylporphyrinato Tetracarbonylcobaltate: A Highly Active, Selective, and Versatile Catalyst for Epoxide Carbonylation

“…The ring expansion of β-lactones to yield γ-lactones has been observed previously with magnesium halides as Lewis acid catalysts. − Two related mechanisms have been proposed. The first involves a dyotropic (concerted) ring expansion, − while the second invokes a transient, zwitterionic species coupled to rapid stepwise migration . A reasonable mechanism for the formation of γ-lactones from the ester-functionalized β-lactones using 1 is shown in Scheme .…”

Enantioselective and Collective Syntheses of Xanthanolides Involving a Controllable Dyotropic Rearrangement of cis‐β‐Lactones

“…[1] A typical example is the Wagner-Meerwein-type dyotropic rearrangement of b-lactones, [2][3][4][5] a rearrangement, which involves concurrent migration of two vicinal s bonds (one CÀO bond and one CÀC bond) to generate the ringenlarged product, that is, g-butyrolactones. [1] A typical example is the Wagner-Meerwein-type dyotropic rearrangement of b-lactones, [2][3][4][5] a rearrangement, which involves concurrent migration of two vicinal s bonds (one CÀO bond and one CÀC bond) to generate the ringenlarged product, that is, g-butyrolactones.…”

“…Weiwu Ren, Yichao Bian, Ziyang Zhang, Hai Shang, Pengtao Zhang, Yuejie Chen, Zhen Yang,* Tuoping Luo,* and Yefeng Tang* Dedicated to Professor Manfred T. Reetz Chemo-, regio-, and stereoselective rearrangements, especially those that lead to skeletal reorganization, are widely appreciated as powerful transformations in organic synthesis. [1] A typical example is the Wagner-Meerwein-type dyotropic rearrangement of b-lactones, [2][3][4][5] a rearrangement, which involves concurrent migration of two vicinal s bonds (one CÀO bond and one CÀC bond) to generate the ringenlarged product, that is, g-butyrolactones. Mechanistically, most of the documented dyotropic rearrangements of b-lactones are concerted and the migrating C À C bond and C À O bond are antiperiplanar in the transition state.…”