Resumo

BRAVO, José A  e  VILA, José L. Mechanistic theoretical proposals for: Alkenes by claisen rearrangement of α allylthio carbenes; Aza-cope rearrangement of 4- butenyliminium ions; 2- substituted pyrrolidine derivatives; Synthesis of perhydrogephyrotoxin, key step; Part v; The organic chemistry notebook, nº 13. Rev. Bol. Quim [online]. 2017, vol.34, n.5, pp.142-149. ISSN 0250-5460.

ABSTRACT This is the thirteenth theoretical assay in the series: “The Organic Chemistry Notebook Series, a Didactical Approach”. The aim of this series of studies is to help students to have a graphical view of organic synthesis reactions of diverse nature. We have taken a series of reactions compiled by W. Carruthers in ‘Some modern methods of organic synthesis’, and we have proposed didactical and mechanistic views for them. This theme is included in the chapter “Formation of carbon-carbon double bonds” in the mentioned text. g-sulphured alkenes can be obtained by Claisen rearrangement of a-allylthio carbenes. A theoretical reaction pathway is proposed here. A short mechanism is proposed for the aza-Cope rearrangement from 4-butenyliminium ions. From this, 2-substituted pyrrolidine derivatives are explained in their reaction step by step under a theoretical approach. With hydroxyl and amino groups as substituents, bicyclic pyrrolidine derivatives are reached. The synthesis of perhydrogephyrotoxin, a natural product, is explained mechanistically here by the using of the preceding reactions.

Palavras-chave : Organic Chemistry; Alkenes; a-Allylthio carbenes; butenyliminium ions; 2- Substituted pyrrolidine derivatives; Perhydrogephyrotoxin; Claisen rearrangement; Aza-Cope rearrangement; Mechanisms of Reactions; W. Carruthers.

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