Affordable Access

Publisher Website

Steroe- and chemoselectivity in 1,3-dipolar cycloaddition reaction of 2-diazopropane with diarylidenacetones

Authors
Journal
Tetrahedron
0040-4020
Publisher
Elsevier
Publication Date
Volume
55
Issue
2
Identifiers
DOI: 10.1016/s0040-4020(98)01056-4
Keywords
  • Article
Disciplines
  • Chemistry

Abstract

Abstract 1,3-Dipolar cycloaddition reaction of 2-diazopropane 1 with diarylideneacetones 2 carried out at 0°C led to a minor Δ 2-pyrazoline monocycloadduct 4 and two diastereoisomeric bicycloadducts 5 and 6. The same addition realised at −60°C has enabled us to observe, beside bis-Δ 2-pyrazolines 5 and 6, the formation of unexpected Δ 3-(1,3,4)oxadiazoline derivatives 9 and 10. These two diastereoisomers result from the addition of 2-diazopropane on the carbonyl of unstable Δ 1-pyrazoline intermediates 3′ and 3″ with an unusual regiochemical way. Oxidation of 5 and 6 gave 3H-pyrazoles 7 and 8.

There are no comments yet on this publication. Be the first to share your thoughts.