Asymmetric intramolecular cyclopropanation of diazo compounds with metallosalen complexes as catalyst: Structural tuning of salen ligand

Biswajit Saha, Tatsuya Uchida, Tsutomu Katsuki

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)

Abstract

Intramolecular cyclopropanation of alkenyl α-diazoacetates and alkenyl diazomethyl ketones was examined by using optically active (ON+)Ru(II)(salen) and Co(II)(salen) complexes as catalysts. For the cyclization of 2-alkenyl α-diazoacetates, Co(II)(salen) complexes 9 and 10 were found to be superior catalysts to the corresponding (ON+)Ru(II)(salen) complexes 4 and 5. On the other hand, (ON+)Ru(II)(salen) complex 2 was found to be the catalyst of choice for the cyclization of 3-alkenyl diazomethyl ketones, and complex 4 was found to be a good catalyst for the cyclization of (E)-4-alkenyl diazomethyl ketones. The present study demonstrates that metallosalen complexes, especially optically active (ON+)Ru(II)(salen) and Co(II)(salen) complexes, can serve as efficient catalysts for the cyclization of alkenyl diazocarbonyl compounds, if a suitable salen ligand is used as the chiral auxiliary.

Original languageEnglish
Pages (from-to)823-836
Number of pages14
JournalTetrahedron Asymmetry
Volume14
Issue number7
DOIs
Publication statusPublished - Apr 4 2003

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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