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Improved preparation of halopropyl bridged carboxylic ortho esters

Original Article

JOURNAL 141

Organic Communications
VOLUME & ISSUE
Year: 2008 Issue: 3 July-September
PAGES
p.48 - 53
STATISTICS
Viewed 1994 times.
AUTHORS
    Richard J. Petroski,
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GRAPHICAL ABSTRACT

ABSTRACT

Bridged ortho esters of 3-halopropyl carboxylic acids were prepared by esterification of 3-methyl-3-hydroxymethyloxetane with 3-bromopropionyl chloride and pyridine in dry THF, followed by rearrangement with boron trifluoroetherate, to afford 1-(2-bromoethyl)-4-methyl-2,6,7-trioxabicyclo[2,2,2]-octane. The 1-(2-iodoethyl)-4-methyl-2,6,7-trioxabicyclo[2,2,2]-octane analogue could not be prepared directly by halogen exchange of 1-(2-bromoethyl)-4-methyl-2,6,7-trioxabicyclo[2,2,2]-octane but could be prepared by halogen exchange of the (3-methyloxetan-3-yl)methyl 3-bromopropanoate with a mixture of sodium iodide and anhydrous sodium sulfate in acetone, followed by rearrangement with boron trifluoroetherate.

 KEYWORDS
  • bridged carboxylic ortho esters
  • 1-(2-bromoethyl)-4-methyl-2
  • 6
  • 7-trioxabicyclo[2
  • 2
  • 2]-octane
  • 1-(2-iodoethyl)-4-methyl-2
  • 6
  • 7-trioxabicyclo[2
  • 2
  • 2]-octane
  • protected 3-halopropionic acid