| Abstract
| - 2-Methyl- and 2-phenyl-substituted oxathianes derived from Myrtenal have been synthesized insatisfying yields. Lithiation of 2-methyl-substituted oxathiane could not be done, but lithiation of2-phenyl-substituted and non-substituted oxathianes could be performed with s-BuLi. Quenchingwith D2O, TMSCl, and/or a carbonyl compound always provides the equatorial product in consistencywith a prefered equatorial orientation of the lithium in the lithiated derivatives. A model is proposedto rationalize the diastereoselectivities observed at C5‘ during reaction of aldehydes with lithiatednon-substituted oxathiane. The model is based on the hypothesis that the lithium, being linkedsimultaneously to the carbon and the oxygen, is shifted toward the oxygen side, making the sterichindrance of this side more effective. Dimeric side products were observed during formation ofthese oxathianes (condensation of various aldehydes with the corresponding hydroxythiol), whichhad not been reported for other oxathianes (derived from pulegone and/or camphorsulfonic acid).
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