Synthesis of Naturally Occurring, Branched Sugars

Synthesis of Naturally Occurring, Branched Sugars 1. Methyl-branched Sugars 

Evermicose (14), having an axial, C-methyl branch, was synthesized by 6-deoxygenation of 58a (R = Me).357 The intermediate was obtained in the ratio of 1 3.4 by epoxidation of the 3-C-methylene derivative of 56a 

Selective removal of the terf-butyldimethysilyl group from 228 to give 230, and oxidation with peroxy acid, gave mainly the epoxide (231). Treatment of 231 with N-methyl-p-toluenesulfonamide gave 232 (hav- 

The structure of pillarose (28) was also determined by synthesis.384 Photochemical addition of ethylene glycol to the ethyl a-D-glycoside of 125 gave 248, which was converted into 249 by 6-deoxygenation, modi- 

pillaroside was also synthesized by reaction of 250a with388 48c and with141 50. y-Octose (29) was also synthesized by introduction of a C-vinyl group into the corresponding glycos-4-ulose.388 

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