L-Ribose synthesis

Synthesis of Some Phosphates of 2-Deoxy-L-ribose," R. Allerton, W. G. Overend, and M. Stacey, Chem. Ind. (London), (1952) 952-953. 

Total Synthesis of D- and L-AUose, D- and L-Talose and of D- and L-Ribose Derivatives... 

The synthesis of L-ribose required two significant innovations for its completion. The first was an efficient synthesis of diisopropyl (chloromethyl)boronate (1) via the in situ preparation of (chloromethyl)lithium by addition of butyllithium to a mixture of chloroiodomethane and triisopropyl borate in THF at — 78°C 18. 

The utility of these metallated 2-allyloxybenzimidazoles was demonstrated further through a synthesis of both d- and L-ribose (81CL1005). The allylcadmium derivative (551) reacted with 2,3-O-isopropylidene-D- and -L-glyceraldehyde to form the corresponding ribo-5-hexenitols (554) with high regio- and stereo-selectivity. Conversion of these products through their oxiranes to d- and L-ribose (557) required only a few additional manipulations as shown in Scheme 122. 

Y. Chong and C. K. Chu, Efficient synthesis of 2-deoxy-L-eryt/fro-pentose (2-deoxy-L-ribose) from L-arabinose, Carbohydr. Res., 337 (2002) 397 102. 

A. Fleetwood and V. Hughes, Convenient synthesis of 2,3-0-isopropylidene-5-thio-D-ribose and 5-thio-D-ribose synthesis of l,4-anhydro-2,3-0-isopropylidene-u-D-ribo-pyranose and l,4-anhydro-2,3-0-isopropylidene-5-thio-u-D-ribopyranose, Carhohydr. Res., 317 (1999) 204-209. 

However, it is rather difficult to search a library of natural sugars for an appropriate sugar derivative for the synthesis of 30. It is necessary to find either 5-deoxy-L-arabinose (61) or 5-deoxy-L-ribose (62), neither of which is available from natural resources [69]. Chemical derivation from easily available sugars is the only way to obtain 61 and 62,however, simple deoxygenation of the terminal alcohol group from L-arabinose (63) and L-ribose (64) generally requires a multi-step process. For example, the deoxygenative transformation... 

Hirashita, T. Kamei, T. Horie, T. Yamamura, H. Kawai, M. Araki, S. Preparation of y-het-erosubstituted allylindium and diindium reagents and their reactions with carbonyl compounds./. Org. Chem. 1999, 64,172-177. Yamaguchi, M. Mukaiyama, T. The stereoselective synthesis of d- and L-ribose. Chem. Lett. 1981, 1005-1008. 

Crystalline L-altrose was described in 1934 by Austin and Humoller. After improving the methods for the preparation of L-ribose," they applied the cyanohydrin synthesis to 30 g. of that sugar and obtained 17 g. of crystalline calcium L-altronate and 14.5 g. of crystalline L-allono-7-lactone. Reduction of the latter with sodium amalgam yielded crystalline L-allose. The calcium L-altronate, by appropriate reactions, was converted to L-altrose, and the last of the sixteen theoretically possible aldohexoses had been prepared. Data on L-altrose and its derivatives are included in Table I. 

SCHEME 13.37 Synthesis of L-ribose with a polymer-supported glycoaldehyde anion equivalent... 

L-Nucleosides represent a class of nucleoside analogs with an excellent profile for antiviral activity combined with minimal host toxicity [105]. Synthesis of new L-nucleosides can use L-ribose and 2-deoxy-L-ribose as starting materials. Synthetic preparations of L-ribose from natural epimeric L-aldopentoses such as L-arabinose or L-xylose has recently been reviewed [106]. The simpler approach used an oxidation-reduction at C-2 from L-arabinose as depicted in Scheme 18 [107, 108]. 

Most of the syntheses for an efficient preparation of 2-deoxy-L-ribose used L-arabinose as the starting material. Fleet and co-workers have developed a practical procedure for the synthesis of 2-deoxy-L-ribose from a readily available... 

In a second synthesis, Gigg and Gigg30 started from 2,3,5-tri-O-benzyl-4-deoxy-4-phthalimido-L-ribose (25), which was obtained... 

Preparation. L-Altrose can be prepared by the Kiliani synthesis, starting from L-ribose.79 More recently, an efficient synthesis of L-altrose starting from glucose has been reported.80... 

P. Soro, G. Rassau, P. Spanu, L. Pinna, F. Zanardi, and G. Casiraghi, Total synthesis of 2,4-diamino-2,4-dideoxy-L-arabinose and 2,4-diamino-dideoxy-L- ribose, J. Org. Chem., 61 (1996) 5172-5174. 

An unusual formyl ketone equivalent which has been used for the synthesis of biopterin (10, X = H) via the actyl derivative 10 (X = Ac) is the phenylhydrazone of 5-deoxy-L-ribose (9) which has been condensed with 2,5,6-triaminopyrimidin-4(3/7)-one.78... 

The first total synthesis of siastatin B (1) was achieved from L-ribose by protection of the 2,3-diol, followed by introduction of an azide group on C-5 and oxidation of the anomeric hydroxyl group to give 5-azido-5-deoxy-2,3-0-isopropylidene-L-ribonolactone... 

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