Synthesis of 3,6-dihydro-2H-pyran-2-ones via cationic palladium(II) complex-catalyzed tandem [2+2] cycloaddition-allylic rearrangement of ketene with α,β-unsaturated aldehydes and ketones

Tetsutaro Hattori, Yutaka Suzuki, Yuuichi Ito, Daido Hotta, Sotaro Miyano

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

Treatment of ketene with α,β-unsaturated aldehydes and ketones in the presence of [Pd(dppb)(PhCN)2](BF4)2 leads to the formation of 4-vinyloxetan-2-ones, which rearrange under the conditions to give 3,6-dihydro-2H-pyran-2-ones in a variety of yields, depending on the substituents. Asymmetric induction with up to 57% de has been achieved by using α,β-unsaturated aldehydes bearing an asymmetric carbon center at the β-position. A zwitterion generated by heterolytic cleavage of the C(4)-O bond of the 4-vinyloxetan-2-one is considered to be an intermediate in the allylic rearrangement. Ethanolysis of 3,6-dihydro-6-methyl-2H-pyran-2-one under acid conditions, followed by saponification of the resulting ethyl 2,4-hexadienoate (ethyl sorbate), gives sorbic acid in 90% yield.

Original languageEnglish
Pages (from-to)5215-5223
Number of pages9
JournalTetrahedron
Volume58
Issue number26
DOIs
Publication statusPublished - 2002 Jul 24

Keywords

  • Allylic rearrangement
  • Cycloaddition
  • Lactones
  • Lewis acid catalysts

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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