Donor product

En2yme Electron donor Product Coen2yme and other components Electron acceptor... 

Entry Substrate Hydrogen donor Product Initial TOP ... 

This review discusses the need to develop a universal donor product for MSC therapy. Such... 

Two-carbon donor/product Malonyl CoA donor of one acetyl group Acetyl CoA product of 1 P-oxidation... 

Bacterial group Type of photosynthesis Pigment in primary photoactivation Electron donors Products Carbon sources... 

Compound reduced Hydrogen donor Product Yield, %... 

In DERA reactions, where acetaldehyde is the donor, products are also themselves aldehydes. In certain cases a second aldol reaction will proceed until a product has been formed that can cyclize to a stable hemiacetal.71 For example, when a-substituted aldehydes were used, containing functionality that could not cyclize to a hemiacetal after the first aldol reaction, these products reacted with a second molecule of acetaldehyde to form 2,4-dideoxyhexoses, which then cyclized to a hemiacetal, preventing further reaction. Oxidation of these materials to the corresponding lactone, provided a rapid entry to the mevinic acids and compactins (Scheme 5.43). Similar sequential aldol reactions have been studied, where two enzyme systems have been employed72 (Scheme 5.44). The synthesis of 5-deoxy ketoses with three substitutents in the axial position was accomplished by the application of DERA and RAMA in one-pot (Scheme 5.44). The long reaction time required for the formation of these thermodynamically less stable products, results in some breakdown of the normally observed stereoselectivity of the DERA and FDP aldolases. In a two-pot procedure, DERA and NeuAc aldolase have... 

Reactions Catalyzed by DERA Acceptor Donor Product... 

Faulkner and coworkers (27., ), have also studied the interaction of Ru(bpy)32+ with zeolite X. Luminescence lifetime measurements and emission spectra were used to study electron transfer quenching of the electron donors N,N,N, N -tetramethyl-p-phenylenediamine and 10-phenyl-phenothiazine. Lifetime measurements show at least two modes of quenching for the interaction of Ru(bpy)32+ ions with these donors. Products of these electron transfer reactions were isolated and these experiments show that the zeolite can separate the products of light induced electron transfer. 

Sensitizer Catalyst or relay Donor Product(s) CO/H2 < ) (mol einstein ) Ref... 

Entry Acceptor Donor Product Isolated yield (%) a p ... 

Water is the usual reaction medium for enzymes however, organic solvents or cyclodextrins can be added to increase the solubility of poorly soluble compoimds. While multienzyme donor recycling systems can be used for in situ donor production [12,19], the following examples utilize stoichiometric donors. 

No. Substrate Biocatalyst Other additives Electron donor Product ee %... 

A soln. of startg. ketone in THF treated with 3 eqs. 0.1 M Smij in THF containing methanol (as proton donor) - product. Y 87% trans xis > 250 1). An electron-withdrawing group on the alkene function is essential in order to prevent pinacol coupling. F.e. incl. isolated cyclopentanols s. E.J. Enholm, A. Trivellas, Tetrahedron Letters 30, 1063-6 (1989). 

The remarkable synthetic potential of BAL is demonstrated by the regiocomplementary benzoin condensation of a,p-unsaturated aldehydes acting as donor or acceptor, respectively. While large aldehydes acted as donors (product type A), small counterparts served as acceptors leading to isomeric olefinic acyloins B in high e.e.s [1497] (Scheme 2.201). 

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