Efficient preparation of chiral C_2-symmetrical 2,6,9-trioxabicyclo[3.3.1]nonanes from cholesteryl benzoate

摘要

The formation of 2,6,9-trioxabicyclo[3.3.1]nonanes from salicylaldehydes and related compounds has been known for quite some time~1,2 and since the discovery of these compounds isolated examples of other dimerizations involving β-hydroxy aldehydes and ketones have been reported, mainly as unwanted side-reactions. In the case of simple anhydro dimers of salicylaldehydes such as 1, the trioxabicyclononane nucleus places the aryl