Highly Selective Synthesis of (E)-3-Methyl-1-trialkylsilyl-3-en-1-ynes via trans-Selective Alkynylation Catalyzed by Cl2Pd(DPEphos) and Stereospecific Methylation with Methylzincs Catalyzed by Pd(tBu3P)2
- 1 May 2003
- journal article
- research article
- Published by American Chemical Society (ACS) in Organic Letters
- Vol. 5 (11) , 1825-1828
- https://doi.org/10.1021/ol030017x
Abstract
trans-Selective (≥98%) monoalkynylation of 1,1-dibromo-1-alkenes and 1,1-dichloro-1-alkenes catalyzed by Cl2Pd(DPEphos) followed by stereospecific methylation with Me2Zn or MeZnX (X= Cl or Br) catalyzed by Pd(tBu3P)2 provides an efficient and stereoselective (≥98%) route to 5, convertible to a wide variety of enynes and conjugated dienes. In the cases of 1,1-dibromo-1-alkenes, the Sonogashira alkynylation may also be satisfactory, but it is distinctly less satisfactory than the alkynylzinc reaction in cases where 1,1-dichloro-1-alkenes are used.Keywords
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