6-Deoxy-L-sorbose

The protonated amino group, however, has no nucleophilic activity, and does not form a hemiacetal an amino sugar can, therefore, be obtained, as a salt, in an otherwise unfavorable form. For example, 6-amino-6-deoxy-L-sorbose can be isolated as the hydrochloride of a furanose form (22) (presumably a). In alkaline solution, immediate ring-expansion to the pyranose form (23) occurs127 this reaction can be reversed under strongly acidic conditions. 4-Amino-4,6-dideoxy-D-glucose hydrochloride forms a 35 65 mixture of the a- and / -pyranose forms in solution.128... 

The Synthesis of Sugars from Simpler Substances. Part IV. Enzymic Synthesis of 6-Deoxy-u-fructose and 6-Deoxy-L-sorbose, L. Hough and J. K. N. Jones,/. Chem. Soc., (1952) 4052-4055. 

Scheme 5.57. TK catalyzed synthesis of 6-deoxy-L-sorbose, precursor to furaneol, was prepared from the readily available reagents acetaldehyde, HPA, and serine.

Carbohydrate synthesis usually involves selective protection of some groups, reaction of the others, then deprotection. The enzymatic aldol reaction can produce some sugars without the need for any protecting groups.251 An example is the preparation of 6-deoxy-L-sorbose (9.39).252... 

In the transketolase-catalysed condensation (see Vol. 27, Chapter 2, Refs. 6,16) of hydroxypyruvate with a mixture of all four 4-deoxytetrose isomers, only the 2R- isomers reacted and only products with S-stereochemistry at the new chiral centre (C-3), le., 6-deoxy-D-fhictose and 6-deoxy-L-sorbose, were formed." A preparation of D- and L-foictose by enzyimc tddol condeos on is referred to below (Ref. 23), and the enzymic conversion of D- and L- r> thro-peittulose, D4i ose and D-psicose to the corre randk 3,4-rhreo-compounds is covered hi Part 4 tsi dds Chtqner (Rrf. 65). 

The 6-deoxy-L-talose derivative 14 was the major product of osmium mtroxide hydroxylation of the alkene 13, itself prepared from di-O-acetyl-L-rhamnal by allylic rearrangement followed by Mitsunobu inversion at C-4.U 6-Deoxy-D- ructose and 6-deoxy-L-sorbose were obtained as a separable mixture from the transketolase-catalysed reaction of hydroxypyruvate with 2,3-dihydroxybuQialdehyde (mixture of isomers) (Scheme 4). ... 

Isopropylidene-L-sorbofuranose has been selectively chlorinated (Ph3P,CQ4,Py) to give, after hydrolysis, 6-chloro-6-deoxy-L-sorbose. The above starting material was also treated with MsCl in DMF and then subsequent hydrolysis gave l,6-dichloro-l,6-dideojqr-L-sorbose. ... 

Condensation of (5)-lactaldehyde with dihydroxyacetone phosphate in the presence of fructose diphosphate aldolase gave the 6-deoxyketose phosphate 12, and this, on treatment with acid phosphatase and then with sucrose synthase in the presence of UDPG, was converted into the 6-deoxy-L-sorbose disaccharide 13.1 ... 

Deoxy-L-sorbose i-phosphate is formed from L-fuculose i-phosphate with a 3-epimerase from Lactobacillus pentosus. ... 

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