Nine-carbon sugars synthesis

A much more lengthy route from glucose giving only the (—)-enantio-mer of frontalin has been reported by Ohrui and Emoto (66). This synthesis, as well as that reviewed above share the common defect that some of the original carbons of the sugar are lost during periodate oxidations. If it is considered that the formation of C-C bonds is nine-tenths of synthetic organic chemistry, then the need for reticence in the use of sodium meta-periodate is warranted. This has been of prime consideration in the approaches to exo-brevicomin which follow. 

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