Highly Regio- and Stereoselective Alkylation of vic-Bis(phenyltelluro)alkenes with Organocuprates
摘要:
Alkylation of vic-bis(phenyltelluro)alkenes 1 with lithium dialkylcuprates takes place regioselectively at the terminal carbon of 1 to provide the corresponding 1-alkyl-2-phenyltelluroalkenes (2) stereoselectively in good yields.
Addition of chalcogenolate anions to terminal alkynes using microwave and solvent-free conditions: easy access to bis-organochalcogen alkenes
作者:Gelson Perin、Raquel G. Jacob、Luiz G. Dutra、Francisco de Azambuja、Greice F.F. dos Santos、Eder J. Lenardão
DOI:10.1016/j.tetlet.2005.11.158
日期:2006.2
We present here the reaction of diphenyl dichalcogenides (Se and Te) with propargyl alcohols using alumina supported sodium borohydride under solvent-free conditions. This efficient and improved method is general and furnishes the corresponding vinyl chalcogenide preferentially with a Z configuration. We also observed that when the same protocol was applied to phenyl acetylene, the (E)-bis-organochalcogen alkenes were obtained in good yields and high selectivity. The use of MW irradiation facilitates the procedure and accelerates the reaction. (c) 2005 Elsevier Ltd. All rights reserved.
Ogawa A., Tsuboi Y., Obayashi R., Yokoyama K., Ryu I., Sonoda N., J. Org. Chem, 59 (1994) N 7, S 1600-1601
作者:Ogawa A., Tsuboi Y., Obayashi R., Yokoyama K., Ryu I., Sonoda N.
DOI:——
日期:——
Photo-Induced Ditelluration of Acetylenes with Diphenyl Ditelluride
stereoselectively to provide only (E)-vic-bis(phenyltelluro)alkenes. Contrary to this, activated acetylenes like phenylacetylene give rise to a mixture of E- and Z-isomers of vic-bis(phenyltelluro)alkenes. Since the obtained vic-bis(phenyltelluro)alkenes indicate absorption in the near-UV, irradiation with near-UV light in solvent causes a novel reverse reaction of the adducts to the starting acetylenes and diphenyl
Alkylation of vic-bis(phenyltelluro)alkenes 1 with lithium dialkylcuprates takes place regioselectively at the terminal carbon of 1 to provide the corresponding 1-alkyl-2-phenyltelluroalkenes (2) stereoselectively in good yields.