Full Research Paper

Mechanistic aspects of the isomerization of Z-vinylic tellurides double bonds in the synthesis of potassium Z-vinyltrifluoroborate salts

Hélio A Stefani^1,2,3, Rafael C Guadagnin¹, Artur F Keppler³, Giancarlo V Botteselle¹, João V Comasseto³ and Carlos A Suganuma¹

¹Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, Brazil

²Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, Brazil

³Instituto de Química, Universidade de São Paulo, São Paulo, Brazil

Beilstein Journal of Organic Chemistry 2008, 4:9doi:10.1186/1860-5397-4-9

Published:	5 February 2008

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Abstract

Through direct transmetalation reaction of Z-vinylic tellurides with nBuLi was observed the unexpected isomerization of double bonds leading to potassium E-vinyltrifluoroborates salts in low to moderate yields. Using EPR spin trapping experiments the radical species that promoted the stereoinversion of Z-vinylic organometallic species during the preparation of potassium vinyltrifluoroborate salts was identified. The experiments support the proposed mechanism, which is based on the homolytic cleavage of the TenBu bond.

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