Improved preparation of halopropyl bridged carboxylic ortho esters

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]-octa...

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Bibliographic Details
Published in:Organic communications 2008-07, Vol.1 (3), p.48
Main Author: Petroski, Richard J
Format: Article
Language:English
Online Access:Get full text
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Summary: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.
ISSN:1307-6175