An Unexpected Tandem Reaction between N-Butadienyl-N-alkylketene N,O-Trimethylsilylacetals of Propionamide and Activated Dienophiles like N-Phenyl-maleimide or Acryloyl Chloride

Authors

  • Marcel Baak
  • Yves Rubin
  • Andreas Franz
  • Helen Stoeckli-Evans
  • Laurant Bigler
  • Jürgen Nachbauer
  • Reinhard Neier

DOI:

https://doi.org/10.2533/chimia.1993.233

Abstract

Starting from the N-butadienyl-N-alkylpropionamides 1a-1c the corresponding N,O-trimethylsilylacetals could be obtained using the mixture of LDA and trimethylsilyl chloride in THF. The unexpected reaction sequence Diels-Alder reaction/acylation between the N-butadienyl-N-alkylketene N,O-trimethylsilylacetal of propionamide (2a-2b) and N-phenylmaleimide produced tricyclic products rac-5a-rac-5b and bicyclic products rac-6arac-6b with high diastereoselectivity. The reaction of the N,O-trimethylsilylacetals 2a and 2c with acryloyl chloride in a similar sequence gave the bicyclic products rac-8a and rac-8c. The stepwise synthesis of bicyclic systems of this general structure could only be successfully executed in 26% yield treating the Diels-Alder product rac-10 with LDA.

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Published

1993-06-30

How to Cite

[1]
M. Baak, Y. Rubin, A. Franz, H. Stoeckli-Evans, L. Bigler, J. Nachbauer, R. Neier, Chimia 1993, 47, 233, DOI: 10.2533/chimia.1993.233.