Erythritol, 0-isopropylidene

The synthesis began with the treatment of 3,4-anhydro-l,2-0-isopropylidene-D-erythritol 90 with 2-alkyl-2-lithio-l,3-dithiane 92 to give 93 (Scheme 16). Reductive desulfurization of 93 and transacetalization of the resulting 94 by the following reaction sequence (1. acidic hydrolysis 2. protection of the primary hydroxyl group 3. ketalization and 4. basic hydrolysis) afforded the primary alcohol 95. The Swern oxidation of 95 yielded the aldehyde 96. 

The reaction of l,2 5,6-di-0-isopropylidene-D-mannitol with the metal oxo complex, (CsMesjReOs, in the presence of triphenylphosphine effected a deox-ydehydration reaction, and gave ( )-2. The same reaction applied to erythritol gave only 1,3-butadiene. ... 

C-Methyl-D-erythritol 4-phosphate (4), a key isoprenoid precursor in the mevalonate-independent pathway leading to isopentenyl diphosphate, has been synthesized in eight steps from 1,2-0-isopropylidene-a-D-xylofuranose in such a way as to facilitate the incorporation of C or radiolabels. Syntheses of the non-phosphorylated derivative, 5, and its L-threitol diastereomer, 6, from d-glucose and D-galactose respectively, have also been reported. 3p-(5 -D-Ribityl)cholestane (7), a putative biological precursor for fossil 3-alkylsteranes, has been synthesized from cholestanone by the stepwise and stereoselective construction and subsequent reductive opening of a 3p-(5 -deoxy-5 -yl-D-ribono-l,4-lactone) substituent/... 

Using the n.m.r. method described above,the isopropylidenations of D-ribose diethyldithioacetal and of D-erythritol have been re-examined. The former with acetone-sulphuric acid was shown to give the 2,5 3,4- and the 2,3 4,5-diacetals each in 40% yield and not the 2,4 3,5-diacetal as previously claimed. D-Erythritol gave mainly the 1,2,3,4-di-O-isopropylidene acetal with either acetone or 2,2-dimethoxypropane-toluene-p-sulphonic acid. ... 

Ring and open-chain derivatives of L-erythritol 1,4-dicinnamate have been irradiated yielding products of photochemical asymmetric synthesis, in which intramolecular 2-1-2 cycloaddition occurs to give L-erythritol esters of cyclobutane-1,2-dicarboxylic acid the 2,3-di-O-methyl derivative of l-erythritol gave a high degree of asymmetric induction, whereas the 2,3-0-isopropylidene derivative was much less stereospecific, and gave the opposite cyclobutane enantiomer. ... 

Under conditions of kinetic control (excess of 2-methoxypropene - catalytic p-toluenesulphonic acid) the four diacetonides (2)-(5) were formed from ribitol in 36, 3,12, and 5% yield, respectively, the last two being new compounds. Similarly, erythritol gave 50% and 18%, respectively of the known diacetals (6) and (7) and, in addition, the new 1,3 2,4-derivative (8) as a minor product. With the same reagent, 4,l, 6 -trichloro-4,l, 6 -trideoxy-gfl/acto-sucrose reacted to give the 2, 3 -monoacetonide (9) and traces of the 6-0-(2-methoxy-prop-2-yl) derivative (10). The partial acetylation of these compounds and their conversion to selectively monomethylated products is covered in Chapter 5, and improved procedures for the preparation of di- and tri-O-isopropylidene derivatives of myoinositol in Chapter 18. 

The syntheses of optically active esters of 2,3-0-isopropylidene-erythritol using SAM II lipase has been described. Thus treatment of (4) with the lipase in the presence of vinyl acetate afforded monoacetate (6) in 95% ee. Whereas treatment of (5) with lipase only gave compound (7) in 97% ee. 

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