Methylene acetals have recently attracted more attention as synthetic intermediates or as templates for asymmetric synthesis. Unlike other acetals the formal moiety is stable toward moderate acidic conditions, and easily removed by acetolysis.' It is able to direct stereoselective additions2 and can also behave as a chelating unit for metal-promoted reactions3 We have been interested in diverse aspects of the chemistry of “glycerol formal”, a ca 1:l mixture of 1.3~dioxan-5-01 ...
