Platinum-Catalyzed Cycloisomerization Reactions of Enynes
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- 作者：Alois Fü ; rstner ; Frank Stelzer ; and Hauke Szillat
- 刊名：Journal of the American Chemical Society
- 出版年：2001
- 出版时间：December 5, 2001
- 年：2001
- 卷：123
- 期：48
- 页码：11863 - 11869
- 全文大小：126K
- 年卷期：v.123,no.48(December 5, 2001)
- ISSN：1520-5126
文摘
PtCl2 constitutes an efficient and practical catalyst for a set of different atom economical rearrangementreactions of enynes. This includes (i) a formal enyne metathesis reaction delivering 1,3-dienes, (ii) the formationof polycyclic vinylcyclopropane derivatives, and (iii) an unprecedented O
C allyl shift reaction if unsaturatedethers are employed. Although these transformations produce significantly different structural motifs, theyshare a common mechanism comprising a cationic manifold triggered by the 
-complexation of Pt(II) ontothe alkyne unit of the substrates. Strong experimental support for the proposed mechanism comes fromdeuterium-labeling studies, a careful analysis of the product distribution pattern, and the fact that in somecases PtCl2 can be replaced by simple Lewis or Br
nsted acids as the catalysts.
C allyl shift reaction if unsaturatedethers are employed. Although these transformations produce significantly different structural motifs, theyshare a common mechanism comprising a cationic manifold triggered by the -complexation of Pt(II) ontothe alkyne unit of the substrates. Strong experimental support for the proposed mechanism comes fromdeuterium-labeling studies, a careful analysis of the product distribution pattern, and the fact that in somecases PtCl2 can be replaced by simple Lewis or Brnsted acids as the catalysts.