Stereospecific chlorotelluration of terminal acetylenes

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• 作者：Ashok K.S. Chauhan^a ; ^{akschauhan2003@yahoo.co.in} ; ^{akschauhan@hotmail.com} ; Swami N. Bharti^a ; ^{goswamiswaminath@yahoo.com} ; Ramesh C. Srivastava^a ; ^{rameshlko@yahoo.co.nz} ; Ray J. Butcher^b ; ^{rbutcher99@yahoo.com} ; Andrew Duthie^c ; ^{aduthie@deakin.edu.au}
• 关键词：Vinyltellurium ; Chlorotelluration ; Secondary bonding interaction ; Steric role
• 刊名：Journal of Organometallic Chemistry
• 出版年：2012
• 期刊代码：64_0022328x
• 类别：ch
• 出版时间：15 June, 2012
• 卷：708-709
• 期：Complete
• 页码：75-81
• 文件大小：562 K

摘要

Chlorotelluration of terminal acetylenes, RCHCH (R聽=聽Ph, rong class="boldFont">1rong>; 4-MeC₆H₄, rong class="boldFont">2rong>; t-Bu, rong class="boldFont">3rong>) with aryltellurium trichlorides and TeCl₄ in refluxing toluene affords (2-chloro-2-organylvinyl)tellurium(IV) dichlorides, Ar[R(Cl)CCH]TeCl₂ (Ar聽=聽1-C₁₀H₇, rong class="boldFont">1Aarong>-rong class="boldFont">3Aarong>; 2,4,6-Me₃C₆H₂, rong class="boldFont">1Ba-3Barong>; 4-MeOC₆H₄, rong class="boldFont">1Carong>) and [t-Bu(Cl)CCH]₂TeCl₂, rong class="boldFont">3arong> respectively. These Te(IV) derivatives on reduction with Na₂S₂O₅ give the corresponding vinyltellurides as oils, except (2,4,6-Me₃C₆H₂)[Ph(Cl)CCH]Te (rong class="boldFont">1Brong>) which is a crystalline solid. The dibromides (rong class="boldFont">1Abrong>-rong class="boldFont">3Abrong>, rong class="boldFont">1Bbrong>-rong class="boldFont">3Bbrong>, rong class="boldFont">3brong>) and diiodides (rong class="boldFont">1Acrong>-rong class="boldFont">3Acrong>, rong class="boldFont">1Bcrong>-rong class="boldFont">3Bcrong>, rong class="boldFont">1Ccrong>) were obtained by the oxidative addition of dihalogens to the tellurides. The stereochemistry of the products has been established with the help of X-ray diffraction studies of rong class="boldFont">1Aarong>, rong class="boldFont">1Barong>, rong class="boldFont">1Bcrong>, rong class="boldFont">1Ccrong>, rong class="boldFont">3Aarong>, rong class="boldFont">3arong> and rong class="boldFont">1Brong>. Intramolecular Te鈰疌l attractive interactions appear to favor the (Z) conformation adopted by the 2-chloro-2-organylvinyltellurium group irrespective of the steric demand of the aryl ligand of the Te(IV) electrophile and the terminal acetylene substituent. The intermolecular Te鈰疿 secondary bonding interactions give rise to dimeric units in the lattices of 1-naphthyl- and anisyltellurium(IV) derivatives, but are absent among the mesityl analogues, consistent with the larger steric requirement of the latter ligand.