Substrates reaction conditions

Both the Wolff-Kishner and Clemmensen reductions of a, -unsaturated ketones give olefins. There has been considerable confusion concerning the exact product composition in the case of A -3-ketones. Wolff-Kishner reduction gives A" -, 5a-A - and 5 -A -olefins, and, depending on the substrate reaction conditions and work-up, any one or more of these may be isolated. (See ref. 287 for a recent review of the Wolff-Kishner reduction.)... 

P,N and non-phosphorus ligands have been most successful in the enantiomeric iridium-catalyzed hydrogenation of unfunctionalized alkenes [5], and for this reason this chapter necessarily overlaps with Chapter 30. Here, the emphasis is on ligand synthesis and structure, whereas Chapter 30 expands on substrates, reaction conditions and reaction optimization. However, a number of specific substrates are mentioned in the comparison of catalysts, and their structures are illustrated in Figure 29.1. 

Substrate Reaction Conditions Products Product Yield Ref... 

Substrate Reaction Conditions Method Conversion (%) Product(s) Yield (%)... 

Substrate reaction conditions Product ( ) point C) References... 

Figure 4.3 Catalytic results of the oxidation of various organic substrates over the YNU-20 and A-50 catalysts. H202 based conv. (%) the percent used for the oxidation of substrates. Reaction conditions for 1-hexene, 0.05 g catalyst, 10 mL methanol, 10 mmol substrate, 10 mmol H202, 60°C, 2 h for n-hexane, 0.1 g...

Entry Substrate Reaction conditions Product Yielda... 

The substrates, reaction conditions and products investigated by Pincock and Yates are shown in Table 4. The rate of bromine disappearance follows in each case the equation ... 

Aldehydes form prior to alcohols. Both branched and linear isomers form. Depending on the alkene substrate, reaction conditions, and catalyst selected, conditions selective for specific compound synthesis can be found . ... 

Entry Substrate ) Reaction conditions Yield, % Ratio - )... 

Substrate Reaction conditions time (h) / temp (°C) Products (GC %)... 

Metal losses during hydrogenation (e. g. metal corrosion, handling losses). Typical loss rates for Pd or Pt are in the range 2-10 %, depending on the specific substrate, reaction conditions, etc. 

Despite several synthetic approaches to the cyciopentane moiety of carbocyclic nucleosides, starting from noncarbohydrate synthons or readily available meso intermediates, no universally applicable methodology is yet available for the asymmetric synthesis of these compounds (28-31). An efficient access to chirality is via enantioselective resolution of a prochiral or a meso intermediate prior to the addition of the purine or pyrimidine base. For example, pig liver esterase (PLE) has been used in a chemoenzymatic approach to the synthesis of optically active (-l-aristeromycin and (-)-neplanocin (32), whereas cyclic y-acetamido esters were resolved to obtain (-)-4 d5-amino-2,3-trflTis-dihy-droxy hydroxymethyl cyciopentane as a key intermediate in the synthesis of carbocyclic nucleosides (33). Although hydrolytic enzymes often display a limited degree of enan-tiospecificity with such unnatural substrates, reaction conditions can in many cases be optimized to improve the enantioselectivity (34). 

Substrate Reaction conditions Product Stereo chemi stry Reference... 

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