Roush allylboronation preparation

The biologically important 2-deoxypentoses can be prepared readily by the two-carbon chain elongation of 2,3- -isopropylidene-D-glyceraldehyde following Roush s allylation method (Scheme 13.54), relying on the highly diastereoselective additions of enantiomerically pure allylboronates derived from (R,R) and (5, 5 )-tartaric acid [100]. Similarly, the 2,6-dideoxyhexose derivative 155 was obtained by Roush and Straub (Scheme 13.54) [101]. 

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