Glyceraldehyde synthesis

Synthesis from o-glyceraldehyde Synthesis of (-)-prosophylline (1) from D-glyceraldehyde acetonide (64) has been reported (Scheme 7). The enantioselective al-lylation of aldehyde 64 with (S,S)-75 afforded the homoallyl alcohol 65 in 86% yield. Protection of 65, as the benzyl derivative, followed by hydroboration and transformation to... 

TKsubstrate pNZYTffiS IN ORGANIC SYNTHESIS] (Vol 9) D-Glyceraldehyde-3-phosphate[591-57-l]aldolase-cataly zed additions... 

They accomplish the reduction of 3-phosphoglycerate, the primary product of COg fixation, to glyceraldehyde-3-phosphate so that carbohydrate synthesis becomes feasible. 

When carbon rearrangements are balanced to account for net hexose synthesis, five of the glyceraldehyde-3-phosphate molecules are converted to dihy-droxyacetone phosphate (DHAP). Three of these DHAPs then condense with three glyceraldehyde-3-P via the aldolase reaction to yield 3 hexoses in the form... 

Write a balanced equation for the synthesis of a glucose molecule from ribulose-l,5-bisphosphate and COg that involves the first three reactions of the Calvin cycle and subsequent conversion of the two glyceraldehyde-3-P molecules into glucose. 

Scheme 11.—Synthesis of l-deoxy-D-tftreo-pentulose from D-glyceraldehyde.

With L-glyceraldehyde as substrate, the same extract catalyzed a half-gram scale synthesis of 1 -deoxy-L-f/ueo-pentulose. 

NeuA, has broad substrate specificity for aldoses while pyruvate was found to be irreplaceable. As a notable distinction, KdoA was also active on smaller acceptors such as glyceraldehyde. Preparative applications, for example, for the synthesis of KDO (enf-6) and its homologs or analogs (16)/(17), suffer from an unfavorable equilibrium constant of 13 in direction of synthesis [34]. The stereochemical course of aldol additions generally seems to adhere to a re-face attack on the aldehyde carbonyl, which is complementary to the stereoselectivity of NeuA. On the basis of the results published so far, it may be concluded that a (31 )-configuration is necessary (but not sufficient), and that stereochemical requirements at C-2 are less stringent [71]. 

The D-fructose 1,6-bisphosphate aldolase (FruA EC 4.1.2.13) catalyzes in vivo the equilibrium addition of (25) to D-glyceraldehyde 3-phosphate (GA3P, (18)) to give D-fructose 1,6-bisphosphate (26) (Figure 10.14). The equilibrium constant for this reaction of 10 strongly favors synthesis [34]. The enzyme occurs ubiquitously and has been isolated from various prokaryotic and eukaryotic sources, both as class I and class II forms [30]. Typically, class I FruA enzymes are tetrameric, while the class II FruA are dimers. As a rule, the microbial class II aldolases are much more stable in solution (half-lives of several weeks to months) than their mammalian counterparts of class I (few days) [84-86]. 

Figure 10.46 Application of ThrA catalysis for the stereoselective synthesis of dihydroxyprolines from glyceraldehyde, and an adenylamino acid for RNA mimics (a). ThrA based preparation of precursors to the immunosuppressive lipid mycestericin and the antibiotic thiamphenicol (b).

Another application of diastereoselective nitro-aldol reactions catalyzed by Bu4NF-3H20 is demonstrated in a simple synthesis of l,4-dideoxy-l,4-imino-D-mannitol (DIM) and amino analogues (Eq. 3.85).134 The nitro-aldol reaction of nitro compounds bearing a-oxy or a-amino function with glyceraldehyde leads to nitrohexitols, which can be reduced to the corresponding amino compounds. Cyclization gives iminopolyols, as shown in Eq. 3.85. 

Various kinds of chiral acyclic nitrones have been devised, and they have been used extensively in 1,3-dipolar cycloaddition reactions, which are documented in recent reviews.63 Typical chiral acyclic nitrones that have been used in asymmetric cycloadditions are illustrated in Scheme 8.15. Several recent applications of these chiral nitrones to organic synthesis are presented here. For example, the addition of the sodium enolate of methyl acetate to IV-benzyl nitrone derived from D-glyceraldehyde affords the 3-substituted isoxazolin-5-one with a high syn selectivity. Further elaboration leads to the preparation of the isoxazolidine nucleoside analog in enantiomerically pure form (Eq. 8.52).78... 

Clavulanic acid is synthesized by the condensation of L-arginine and D-glyceraldehyde-3-phosphate (G3P) as the first step [75,77] (Figure 12.2). A series of experiments revealed that the synthesis of clavulanic acid was limited by the availability of the C3 precursor, resulting from the species s limited ability to assimilate glucose [78]. Thus, the enhancement of clavulanic acid production requires alleviation of competition from other pathways for a C3 precursor [79]. 

Stereocontrolled influence of precomplexing additives was used in the synthesis of (2R,3S)- and (2S, 3 S)-2-amino-l,3,4-butanetrioles resulting from a stereo-divergent hydroxymethylation of D-glyceraldehyde nitrones (Fig. 2.24). The obtained syn- and anti-adducts were further converted into C-4 building blocks and to (i-hydroxy-a-amino acids (570). 

The reaction of O-methyl-O-tert-butyldimethylsilyl ketene acetal with N-benzyl- and A-methyl-2,3-O-Mopropylidene D-glyceraldehyde nitrones (292), in the presence of boron trifluoride etherate, affords the corresponding isoxazolidine-5-ones in high yields. These compounds were successfully applied as key intermediates in the synthesis of isoxazolidinyl nucleosides of the L-series (Scheme 2.177) (638). 

Optically pure glyceraldehyde acetonides are widely used in the synthesis of enantiomerically pure compounds (EPC synthesis).1 2 3 4 5 Whereas D-(R)-glyceraldehyde acetonide is easily obtained from the inexpensive D-mannitol,6 7 there are only a limited number of practical syntheses of the enantiomeric L-(S)-glyceraldehyde acetonide.8 9 Difficulties arise from different sources 1) availability of the starting material diisopropylidene-L-mannitol 2) length of the synthesis 10 3) nature of the reactants used mercury acetate, mercaptans, lead tetraacetate, ozone at -78°C, 4) moderate yields.11 14... 

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