L-Apiose

Acid chloride 611 was used320 as the substrate in the synthesis of L-apiose (53) (see Scheme 10). Further workM0,s n extended the use of... 

The chemical synthesis of L-apiose has been accomplished by starting with (a) L-threaric [(+)-tartaric] acid,19 (b) 2,3-0-... 

A mixed aldol reaction129 of formaldehyde with 1,2-0-isopropylidene-a-D-xy/o-pentodialdo-l,4-furanose (37) in sodium hydroxide solution gave 4-C-(hydroxymethyl)-l,2-0-isopropylidene-L-fftreo-pentofuranose (38). Hydrolysis of compound 38 with aqueous acid, to give 39, followed by oxidation with bromine in the presence of calcium carbonate, resulted in the formation of calcium 4-C-(hydroxymethyl)-L-threo-pentonate pentahydrate (40) which, in turn, was converted into L-apiose (36). These almost simultaneous experiments of Weygand and Schmiechen19 and Schaffer129 were the first published syntheses of L-apiose. 

Schaffer398 described a synthesis of L-apiose by reaction of 170 with formaldehyde, and Horton et al,373 developed a method for extension of sugar chains through ethynylation of 170 and other aldehydo compounds by the Grignard reaction. 

Overend, W G, White, A C, Williams, N R, Branched-chain sugar Part XII. Branched-chain sugars derived from methyl 2,3-0-isopropylidene-p-L-ery/hro-pentopyranosid-4-ulose, and a synthesis of L-apiose, Carbohydr. Res., 15, 185-195, 1970. 

Within this extremely important group of monosaccharides [9,107] the typical representative bears a branched functional group at any position except the anomeric carbon, but most commonly at the C-2 and C-3, as in natural L-streptose, D-hamamelose, or L-apiose. 

A new synthesis of L-apiose uses the photochemical reaction of the (-)-8-phenylmenthyl ester of phenylglyoxylic acid with 2,2-di-methyl-1,3-dioxalen to generate the oxetan (18) with 96% d.e., leading in turn to the branched-chain sugar (19) and the apioside (20)(Scheme 7). ... 

Care needed with naming and numbering of derivs. C-3 is not a chiral centre in the acyclic sugar. In L-Apio-a-D-furanose for example, l- defines the config. at C-2 (L-apiose), while D-defines the config. at C-3 (D-furanosyl stereoisomeric form of L-apiose). 

A soln. of L-apiose a-benzylphenylhydrazone in 75%-ethanol treated with freshly distilled formaldehyde soln., coned, on a water bath to half its volume, more formaldehyde soln. added, and refluxed 4 hrs. L-apiose. Y 82% as sirup. F. Weygand and R. Schmiechen, B. 92, 535 (1959). 

The cleavage of oxetans formed in the Paterno-Biichi reaction has also been used with effect.Thus an extremely simple and efficient synthesis of D,L-apiose (53) involved the base-induced cleavage of the oxetan (52), derived from diacetoxyacetone and vinylene carbonate (Scheme 15). A reductive cleavage of... 

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