Resumo

BRAVO, Jose A  e  VILA, Jose L. Reordenamiento de claisen de eteres alil vinilicos para dar alquenos, Parte IV; propuestas mecanicistas teoricas; serie el cuaderno de quimica organica, Un enfoque didactico, N° 12. Rev. Bol. Quim [online]. 2017, vol.34, n.2, pp.40-49. ISSN 0250-5460.

This is the twelfth 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. In the present chapter we expose more Claisen rearrangements variations. The Claisen rearrangement can be regarded as a particular case of Cope's rearrangement, hence, on the basis of the structural theory and the known mechanisms of organic chemistry, we have proposed theoretical mechanisms for the synthesis of dienes from 2-methyl-3-phenyl-1,5-hexadiene at low temperature. We have proposed a mechanism for the synthesis of δԑ-unsaturated aldehydes and ketones through the oxy-Cope rearrangement of 1,5-hexadienes. We've described the mechanism for the key step of the synthesis of the sesquiterpene (±)-juvabione. The mechanistic views of the synthesis of the natural germacrane sesquiterpenes are proposed. We have proposed a mechanism for the thio Claisen rearrangement of allyl vinyl sulfides in the transformation into ƴδ5-unsaturated carbonyl compounds, for example the preparation of 4-tridicenal and the [2,3]sigmatropic rearrangement of allylsulphonium ylids like in the preparation of y-cyclocitral.

Palavras-chave : Organic Chemistry; Alkenes; Allyl vinyl ethers; Claisen rearrangement; Mechanisms of Reactions; W. Carruthers.

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