Regio- and stereoselective synthesis of Z-vinylic tellurides from propargylic alcohols: a route to chiral Z-enynes
作者:Cristiano Raminelli、Nathalia C. da Silva、Alcindo A. Dos Santos、André L.M. Porto、Leandro H. Andrade、João V. Comasseto
DOI:10.1016/j.tet.2004.10.087
日期:2005.1
tert-Butyldimethylsilyl ethers of propargylic alcohols are hydrotellurated regioselectively to give 1,2-Z-vinylic tellurides. Enantiomerically pure propargylic alcohols give enantiomerically pure vinylic tellurides, which are coupled with alkynes under Pd catalysis to give enantiomerically pure allylic enynols.
Chemoselective reduction of β-butyltellanyl α,β-unsaturated carbonyl compounds to allylic alcohols
作者:Alcindo A. Dos Santos、Priscila Castelani、Bruno K. Bassora、José C. Fogo Junior、Carlos E. Costa、João V. Comasseto
DOI:10.1016/j.tet.2005.06.090
日期:2005.9
(Z)-β-Butyltellanyl α,β-unsaturated carbonyl compounds were stereoselectively produced by hydrotelluration of alkynones or by an addition/elimination sequence from enol tosylates. The β-butyltellanyl-enones were chemoselectively reduced with NaBH4/MeOH, NaBH4·CeCl3·7H2O/MeOH and DIBAL-H systems to the corresponding allylic alcohols with retention of the Z stereochemistry.
Carbon–carbon bond formation by means of organotellurium compounds
作者:R Barrientos-Astigarraga
DOI:10.1016/s0022-328x(00)00828-7
日期:2001.3.30
vinylic halides, phosphates, sulphonates and acetates leading to the Z vinylic telluride exclusively. Tellurides are transmetallated with easily available organometallic reagents to give valuable synthetic building blocks (e.g. organolithiums and organocuprates). Reaction of vinylic tellurides with alkynes under Pd catalysis or with organocuprates gives the coupling products with retention of the double bond
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.
Tellurium in organic synthesis: synthesis of bioactive butenolides
作者:Bruno K. Bassora、Carlos E. Da Costa、Rogério A. Gariani、João V. Comasseto、Alcindo A. Dos Santos
DOI:10.1016/j.tetlet.2006.12.063
日期:2007.2
Reduction of (Z)-β-butyltelluro-enones gives the corresponding γ-hydroxy vinylic tellurides with retention of the double bond configuration. Reaction of γ-hydroxy vinylic tellurides with 2 equiv of n-butyllithium produces 1,4-C,O-dianions, which on reaction with carbon dioxide give the corresponding butenolides.