Synthesis of some fenchyl-substituted alkenes and enol-ethers containing 3-oxyphenyl substituents by the Barton-Kellogg reaction

Journal of the Brazilian Chemical Society

Luiz Francisco M. L. Ciscato²  Erick L. Bastos¹  Fernando H. Bartoloni²  Wolfgang Günther¹  Dieter Weiss¹  Rainer Beckert¹  Wilhelm Josef Baader² 

[1] ,Universidade de São Paulo Instituto de Química Departamento de Química FundamentalSão Paulo SP ,Brazil

关键词: Barton-Kellogg olefination;    hindered alkenes;    diazo compounds;    thioketone;    fenchone;   

DOI  :  10.1590/S0103-50532010001000014

来源: SciELO

【 摘 要 】

The synthesis of one fenchyl-substituted alkene and two enol-ethers, containing 3-oxyphenyl substituents by the Barton-Kellogg reaction is described. The tri-substituted aromatic fenchyl-alkene 1a was prepared in 53% yield from thiofenchone and a diazoanisole; whereas enol-ethers 1b and 1c were obtained (95 and 75% yield, respectively) using an inverse approach based on diazofenchone and aromatic thionoesters. A mixture of Z and E isomers was obtained in all cases; isomer attribution and quantification has been carried out by analysis of NMR spectroscopic data assisted by theoretical calculations (E/Z ratio: 1a = 0.72, 1b = 2.2, 1c = 1.8). Reaction proceeds with low stereoselectivity leading to the preferential formation of diastereoisomeric olefins and enol-ethers where the aromatic substituent resides at the side of the two fenchyl methyl groups.

【 授权许可】

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