Stereoselective Control In Phase-transfer Catalysed Reactions

Stereoisomers are also obtained from chloroacetonitrile and asymmetrically substituted ketones [5] and chloromethylsulphones react specifically with aldehydes to yield only the frans-substituted oxiranes [6], 

Stereochemical control of Darzen s reaction of a-chlorophenylacetonitrile with benzaldehyde by phase-transfer catalysts 

The regiospecificity of the exclusive O-acylation [8] and O-phosphorylation [9] of P-dicarbonyl compounds (Chapter 3) also illustrates the effect of phase-transfer catalysts on the stereochemical course of reactions. Similarly, directed reduction of P-hydroxy ketones using tetramethylammonium trisacetoxyborohydride leads to the preferential formation of the anti dihydroxy system in high yield with a stereoselectivity 95% [10] (Section 11.4). 

Effect of phase-transfer catalysts on the stereochemical formation of 

Solvent system Without catalyst With catalyst 

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Stereoselective Control in Phase-transfer Catalysed Reactions... 

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