Enzyme-catalyzed aldol addition reactions

Eyrisch, O, Sinerius, G, Fessner, W-D, Eacile enzymic de novo synthesis and NMR spectroscopic characterization of D-tagatose 1,6-bisphosphate, Carbohydr. Res., 238, 287-306, 1993. Henderson, I, Sharpless, KB, Wong, C-H, Synthesis of carbohydrates via tandem use of the osmium-catalyzed asymmetric dihydroxylation and enzyme-catalyzed aldol addition reactions, J. Am. Chem. Soc., 116, 558-561, 1994. 

Recent Advances in Enzyme-Catalyzed Aldol Addition Reactions... 

RECENT ADVANCES IN ENZYME-CATALYZED ALDOL ADDITION REACTIONS... 

Recent advances in enzyme-catalyzed aldol addition reactions for biocatalytic carbon-carbon bond formation by means of aldolases are described. They offer an exceptionally stereoselective and green tool for asymmetric framework construction and preparation of innovative molecules with engineered enz5unes. 

Several cyditol derivatives of varying ring size, for example, (69)/(70), have been prepared based on an enzymatic aldolization as the initial step. Substrates carrying suitably installed C,H-acidic functional groups such as nitro, ester, phosphonate (or halogen) functionalities made use of facile intramolecular nucleophilic (or radical) cyclization reactions ensuing, or subsequent to, the enzyme-catalyzed aldol addition (Figure 10.27) [134—137]. 

Fessner, W.-D. (2004) Enzyme-catalyzed aldol additions, in Modern Aldol Reactions, vol. 1 (ed. R. Mahrwald), Wiley-VCH, Weinheim, pp. 201-272. 

P. Clapes, 1. loglar, Enzyme-Catalyzed Aldol Additions, in R. Mahrwald (Ed.), Modem Methods in Stereoselective Aldol Reactions, lohn Wiley Sons Ltd, 2013, pp. 475-528. 

W.-D. Fessner, Enzyme-catalyzed aldol additions, in M. Rainer (Ed.), Modern Aldol Reactions. Enolates, Organocatalysis, Biocatalysis and Natural Product Synthesis, Wiley-VCH Verlag GmbH Co. KgaA, Weinheim, 2004, pp. 201 -272. 

Clapes, P. and Joglar, J., Enzyme-catalyzed aldol additions. In Modern Methods in Stereoselective Aldol Reactions, Mahrwald, R., Ed. John Wiley Sons, Ltd Chichester, 2013 pp 475-528. 

There are two distinct groups of aldolases. Type I aldolases, found in higher plants and animals, require no metal cofactor and catalyze aldol addition via Schiff base formation between the lysiae S-amino group of the enzyme and a carbonyl group of the substrate. Class II aldolases are found primarily ia microorganisms and utilize a divalent ziac to activate the electrophilic component of the reaction. The most studied aldolases are fmctose-1,6-diphosphate (FDP) enzymes from rabbit muscle, rabbit muscle adolase (RAMA), and a Zn " -containing aldolase from E. coli. In vivo these enzymes catalyze the reversible reaction of D-glyceraldehyde-3-phosphate [591-57-1] (G-3-P) and dihydroxyacetone phosphate [57-04-5] (DHAP). 

A (3 replacement reaction catalyzed by the PLP-dependent tryptophan synthase converts indoleglycerol phosphate and serine to tryptophan. Tryptophan synthase from E. coli consists of two subunits associated as an a2P2 tetramer (Fig. 25-3). The a subunit catalyzes the cleavage (essentially a reverse aldol) of indoleglycerol phosphate to glyceraldehyde 3-phosphate and free indole (Fig. 25-2, step s).67 The P subunit contains PLP. It presumably generates, from serine, the Schiff base of aminoacrylate, as indicated in Fig. 25-2 (step f). The enzyme catalyzes the addition of the free indole to the Schiff base to form tryptophan. The indole must diffuse for a distance of 2.5 ran... 

FDP aldolase catalyzes the reversible aldol addition reaction of DHAP and d-glyceraldehyde 3-phosphate (D-Gly 3-P) to form d-FDP (Fig. 14.1-1). The equilibrium constant for this reaction has a value of -104 m-1 in favor of FDP formation. The enzyme has been isolated from a variety of eukaryotic and prokaryotic sources, both in type I and type II forms[7 21). Generally, the type I FDP aldolases exist as tetramers (M.W. 160 KDa), while the type II enzymes are dimers (M. W. 80 KDa). For the... 

Figure 14.1-26. Aldol addition reaction catalyzed in v/Vo by KHG aldolase and the donor substrate specificity of this enzyme.

The substrate for the first enzyme-catalyzed reaction of glycolysis is a six-carbon compound (o-glucose). The final product of glycolysis is two molecules of a three-carbon compound (pyruvate). Therefore, at some point in the series of enzyme-catalyzed reactions, a six-carbon compound must be cleaved into two three-carbon compounds. The enzyme aldolase catalyzes this cleavage (Figure 24.12). Aldolase converts o-fructose-l,6-diphosphate into o-glyceraldehyde-3-phosphate and dihydroxyacetone phosphate. The enzyme is called aldolase because the reverse reaction is an aldol addition reaction (Section 19.13). The reaction proceeds as follows ... 

Aldolases are a group of C—C bond forming enzymes with widespread applications. The stereoselective aldol addition reaction catalyzed by aldolases represents an attractive alternative to conventional chiral organic chemistry methods for chemical and pharmaceutical industries. Aldolases are classified according to both their proposed catalytic mechanism and the structure of the donor substrate, their sources and microbial production processes being presented in this chapter. To design appropriate bioreactors for aldol synthesis, the characteristics of aldolase biocatalysts obtained after purification procedures in free and immobilized form are discussed. 

The potential of enzymes as practical catalysts is well described, and their activity and selectivity (stereo-, chemo-, and regioselectivity) for catalyzed reactions cover a broad range. Enzymes clearly constitute very powerful green tools for catalyzing synthetic chemical processes. In this context, the continuous increase of the market for enantiopure fine chemicals places enzymes as suitable catalysts for green synthetic processes. Catalytic promiscuity of enzymes in nonaqueous environments has been widely described and is related to the ability of a single active site to catalyze more than one chemical transformation for example, lipase B from Candida antarctica (CALB) is able to catalyze aldol additions, Michael-type additions, and so on [4]. 

---