Synthesis of substituted α,β-unsaturated δ-lactones from vinyl tellurides
作者:Juliana M. Oliveira、Juliano C. R. Freitas、João Valdir Comasseto、Paulo Henrique Menezes
DOI:10.1016/j.tet.2011.02.029
日期:2011.4
new approach for the synthesis of α,β-unsaturated δ-lactones, a unit present in many natural products with interesting biological activities is described. The approach was based on the use of a vinyltelluride, and it is complementary to the methods using ring-closing metathesis. The sequence was performed in good overall yield with retention of the Z-double bond geometry.
Differentiation and assignment of vinyl telluride regioisomers by <sup>1</sup>
H-<sup>125</sup>
Te <i>g</i>
HMBC
作者:Juliano C. R. Freitas、Dayvson J. Palmeira、Roberta A. Oliveira、Paulo H. Menezes、Ricardo O. Silva
DOI:10.1002/mrc.3826
日期:2012.7
Complete (1) H, (13) C, and (125) Te NMR spectral data for some vinyltellurides are described. The (1) H-(125) Te gHMBC experiment was used for the complete chemical shift assignment and structure elucidation of a mixture of regioisomers. The assignment ((125) Te NMR) and coupling constants (J(H,H) ) for all regioisomers are described for the first time.
Influence of different protecting groups on the regioselectivity of the hydrotelluration reaction of hydroxy alkynes
作者:Juliana M. Oliveira、Dayvson J. Palmeira、João V. Comasseto、Paulo H. Menezes
DOI:10.1590/s0103-50532010000200024
日期:——
The influence of protecting groups on the synthesis of regio- and stereodefined vinyl tellurides derived from the reaction of BuTeNa and propargylic- or homo-propargylic alcohols showed that TIPS silyl ether is useful as a regiodirecting group. The application of the methodology to the synthesis of a fragment of (+/-)-Seselidiol, a natural product, demonstrated the applicability of the new methodology.