Glyceraldehyde reaction with 1,3 dicarbonyl compounds

The imidazoles formed in the reaction of aqueous ammonia with other a-hydroxycarbonyl compounds, for example, the triose DL-glyceraldehyde, and such a-dicarbonyl compounds as 3-deoxy-D-glycero-pentosulose (59), and the 3,6-dideoxy-L-erythro-, D-arabino-, and 3-deoxy-D-erytforo-hexosuloses (60, 61, and 62), respectively, are summarized in Table VIII for reactions in which formaldehyde was added, and in Table IX for reactions in which it was not added. 

Reaction of lithiodithianes with acyl chlorides, esters or nitriles leads to the fOTination 1,2-dicarbonyl compounds in which one of the carbonyl groups is protected as the thioacetal. d76043j44 Optically active amino ketones of type (69) are inepared via acylation of dithiane with an oxazoline-protected (5)-serine methyl ester (Scheme 41). Optically active (5)-2-alkoxy-l-(l,3-dithian-2-yl)-l-propanones were prepaid by the reaction of the corresponding methyl (5)-lactate with 2-lithio-l,3-enantioselective synthesis of (-)-trachelanthic acid. Enantioselective synthesis of L-glyceraldehyde involves the acylation of a dithiane glycolic acid derivative followed by bikers yeast mediated reduction. ... 

Aldol reactions, usually followed by dehydration, of /3-dicarbonyl compounds with the aldehyde forms of substituted nonnitrogenous monosaccharides are also known. 2,3-0-Isopropylidene-D-glyceraldehyde condenses with ethyl acetoacetate in the presence of piperidine, giving the 1,3-dideoxy-3-(ethoxycarbonyl)-5,C-0-isopropyIidenehexulose (54), presumably as a mixture of diastereoisomers, and 1,3,4-trideoxy-3-(ethoxy-carbonyl)-5,6-0-isopropylidene-D-gfi /cero-hex-3-enulose (55). Reaction of... 

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