Enolethers special

In the course of the synthesis173 of oxaprostaglandins from 1,4 3,6-dian-hydro-D-glucitol, the latter was first monotosylated at the 5-position and the ester benzylated, to afford 82. Elimination of the tosyl oxy group under special conditions yields the enolethers 83 and 84 (see Scheme 16) as a 2 1 mixture which can be separated by column chromatography. 

Ketocarboxylic esters condense with AT, as a rule, to give exclusively 7-oxo derivatives (see Scheme 1) an exception is that of a side reaction in a special case (93JHC1325). Esters having instead a 3-acetal or 3-enolether functionality, however, are known to tend to reverse reactivity (e.g., 99EUP947516, 04MI2). 2-Chlorocin-namic acid (15a, Scheme 6) or its ester remarkably also behave so (00CHE1329). 

The plasmalogens occupy a special place in the class of phospho-glycerides. They are phos-phatides in which position 1 of glycerol is linked to a straight-chain aldehyde with 16 or 18 carbons. The hnkage is an enolether type with a dou-... 

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