2-Deoxy-DL-pentoses

A simple synthesis of a glycoside of DL-daunosamine has been devised by Matsumoto and his co-workers. In this approach 1-chloro-l, 4-hexadiene-3-one (77, obtained from crotonyl chloride and vinyl chloride) was converted into 1,1-ethylenedioxy-4 -hexen-3-one (78). cw-Hydroxylation of 78 afforded threo-A o-lon (79). Oximation of 79 and reduction of the oxime gave a single stereoisomeric aminodiol (80) which, after treatment with methanolic hydrogen chloride, yielded methyl a-DL-daunosaminide (74, R = H, R = Me) in 84% yield. Makin and co-workers described two methods leading to both stereoisomeric 2-deoxy-DL-pentoses in the form of their diethyl acetals. In the first method, the readily available 1,l-diethoxy-3-penten-5-ol (81) was directly cri-hydroxylated furnish-... 

In the second synthesis, 1,1,3-triethoxy-4-pentene (84) served as substrate. Epoxidation of the double bond followed by hydrolysis afforded mixture of both stereoisomeric 2-deoxy-DL-pentoses in the form of their 1,1,3-tri-O-ethyl derivatives (85 and 86). 

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