Application of the Oxo Reaction to 2,3-Enes

Preliminary studies of the oxo reaction of ethyl 4,6-di-0-acetyl-2,3-dideoxy-a-D-efj/fhfo-hex-2-enoside (53) have shown that four products are produced, which (by nuclear magnetic resonance studies) are presumed to be the four branched-chain isomers possible.  

The separation of the oxo products (deacetylated or fully acetylated) from the 2,3-ene (54) presented a difficult and challenging problem. Deacetylation of the mixture of products gave products from most of 

A parallel reaction of tetra-0-acetyl-3-deoxy-a-D-erj/ / ro-hex-2-enopyranose with carbon monoxide and deuterium yielded the partially deuterated analogs (57) and (58), which were also separated by gas—liquid chromatography. 

The large coupling-constants of H-2, H-3, and H-4 support the ailerons orientation of these hydrogen atoms, and, therefore, (56) and (58) are penta-0-acetyl-3-deoxy-3-C-(hydroxymethyI)-a-D-glucopyr-anose and penta-0-acetyl-3-deoxy-3-C-(hydroxymethyl)-a-D-glucopyr-anose-2,3, 3 -da. 

The gas —liquid chromatographic re-run of zone A at 180° (see Fig. 10) indicated the presence of two zones, in almost equal proportions, which were presumed to be tetra-0-acetyl-l,5-anhydro-3-deoxy-3-C-(hydroxymethyl)-D-glucitol and -D-altritol, although no definite synthetic evidence has thus far been presented in support of this supposition. 

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