1.1- Diethoxy-3-penten

Stereospecific syntheses of the 1,1-diethyl acetals 45 and 47 were performed by Makin and coworkers.29 trans-5,5-Diethoxy-2-penten-l-ol (44) was cis-hydroxylated with potassium permanganate, to yield the diethyl acetal (45) of 2-deoxy-DL-threo-pentose. Epoxidation of 44 and alkaline hydrolysis of the epoxide 46 gave the diethyl acetal (47) of 2-deoxy-DL-en/thro-pentose. 

Penten 1,1-Diethoxy- VII/1, 374 Peroxid tert.-Butyl-cyclopentyl-... 

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-... 

The nthesis of 2,3-dideoxy-3-C-methylene-D- /ycero-pentofuranose has been achieved by Sharpless epoxidation of 5,5-diethoxy-3-methyl-2-pentenal followed by rearrangement of the product to 2,3-dideoxy-3-C-methylene-D-g/ycero-pentose diethylacetal and, finally, hydrolysis. ... 

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