[4 + 2] Cyclocondensation Reactions of Tungsten鈥揇ihydropyridine Complexes and the Generation of Tri- and Tetrasubstituted Piperidines

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• 作者：Daniel P. Harrison ; Diana A. Iovan ; William H. Myers ; Michal Sabat ; Sisi Wang ; Victor E. Zottig ; W. Dean Harman
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：November 16, 2011
• 年：2011
• 卷：133
• 期：45
• 页码：18378-18387
• 全文大小：1049K
• 年卷期：v.133,no.45(November 16, 2011)
• ISSN：1520-5126

文摘

A new method for the preparation of functionalized piperidines is described in which various dihydropyridine (DHP) complexes of {TpW(NO)(PMe₃)} that are derived from pyridine鈥揵orane undergo [4 + 2] cyclocondensation with enones, enals, nitrosobenzene, and several isocyanates to form [2.2.2] bicyclic species. In several cases the diazabicyclooctene products derived from DHP complexes and isocyanates can be further elaborated into novel syn-2,5-disubstituted and 2,3,6-trisubstituted piperidinamides.