作者:Jeffrey J. Barlow、Michael H. Block、Julian A. Hudson、Alison Leach、Jethro L. Longridge、Brian G. Main、Stuart Nicholson
DOI:10.1021/jo00045a030
日期:1992.9
A number of enantiomerically pure heterocyclic ketals 5 have been prepared, and their acid-catalyzed hydrolysis to the corresponding diols 6 has been studied. During this reaction a rearrangement may occur to give racemic products, and so the kinetics of the two competing reactions have been studied to establish optimum conditions. The rate of rearrangement is independent of pH below the pK(a) of the heterocycle, whereas the rate of ketal continues to increase as pH is lowered. Brief treatment with strong acid has allowed the formation of very pure diols in high yield.