Heptitols synthesis

It will be noticed that the future application of the Fischer cyanohydrin synthesis to n-altrose should lead to two heptitols, one of which (n-altro-D- luco-heptitol) should be the enantiomorph of the known D-gulo-L-talo-heptitol, while the other (o-altro-D-manno-heptitol) should be identical with natural volemitol (D-manno-D-[Pg.12]

During the synthesis of n-apiose, 3-0-benzyl-n-fructose was treated in the same way (Kiliani method), and a crystalline 3-0-benzyl lactone was formed (m.p. 150-152°). Reduction by means of sodium borohydride gave the branched-chain heptitol (75), showing that this method provides an interesting tool for the synthesis of branched-chain sugars. - ... 

Synthesis from aldonolactones The synthesis of p-homonojirimycin (2) from tetra-(9-benzyl-D-glucono-1,5-lactone (56) (Scheme 8) was achieved by treatment of the latter with (methoxymethoxy)methyl lithium to give the a-D-gluco-heptulose derivative 57, which underwent reduction with LiAlITj to produce a mixture of heptitols 58 (1 1 ratio). Oxidation of 58 using Swern oxidation (DMSO-TFAA) gave the heptodiulose 59. Compound 59 was immediately submitted to reductive amination using ammonium formate in the presence of sodium cyanoborohydride to produce 60 in 50% yield from 58. Removal... 

It is interesting that iron carbonyl can be used as a protecting group for dienes. Iron diene complex 491, for example, reacted with 492 in a Mukaiyama aldol reaction (sec. 9.4,C), giving an 81% yield of 493 and 494 in an 84 16 ratio.32 in a synthesis of heptitol derivatives,322 Pearson protected tropone as the iron tricarbonyl derivative (495), and prepared 496 using a multistep sequence before deprotecting the diene to give 497. 

From Chiral Non-carbohydrates - A section on amino-sugars has been included in a review of the synthesis of monosaccharides from non-carbohydrate sources. L-Ristosamine 42 was synthesized by addition of the Cs-synthon 40 (which contains a masked aldehyde function that can be readily demasked by mild acid hydrolysis) to the L-lactaldehyde derivative 41 (Scheme 11). The TBSOP adduct 43 (Vol.27, p.ll4), derived from 2,3-< -isopropylidene-D-glycer-aldehyde, has been converted into 3-amino-3-deoxy-D-altrose 46 by a route involving cis-hydroxylation of its unsaturated lactam moiety and periodate cleavage between C-6 and C-7 of the derived heptitol derivative 45 as key steps (Scheme 12). 3-Amino-3-deoxy-L-allose was obtained by converting 43 to its C-3... 

The configurations of the D-series of some optically active heptitols and the meso forms are illustrated on p. 255. The physical constants of the known heptitols and their acetates, as well as references to their synthesis, are given in Table II. 

Another method for the establishment of the configuration of an alditol obtained synthetically is especially valuable when both of the 2-epimers are optically active. It consists of the synthesis of the same polyol from two different aldoses. Thus, from the fact that D-mannose and L-galactose by the cyanohydrin synthesis yield four heptoses, which on reduction give only three different heptitols, one of which (perseitol) is produced from both D-mannose and L-galactose, the configuration of the four heptoses and three heptitols could be deduced. (For a discussion of these methods and detailed references, see Hudson (64).)... 

The synthesis of the 2,5-disubstituted pyrrolidine 43 from D-mannitol by standard chemistry and the synthesis of pyrrolidines 44 by addition of azomethine ylides to vinylene carbonate " as well as the synthesis of the imino-heptitol 45 from 2,3 5,6-di-0-isopropylidene-a-D-mannofuranose have been reported. 

Amino- and Imino-Alditols.- The synthesis of 1,2-diamino-dideoxy-D-g/yccro-L-manno- and D-g/ycero-L-g/uco-heptitol and their conversion into the same pyrazine (23) on reaction with benzil followed by acetylation and oxidation has been rqx>rted. ... 

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