Reduction of activated carbonyl groups

Reduction of activated carbonyl groups of a-keto esters, benzils, cyclohexane-1,2-dione, and o -ketophosphonates by alkylphosphines afforded the corresponding cr-hydroxy esters or ketones in good to excellent yields. A mechanism has been suggested on the basis of deuterium and 180 labelling experiments.380... 

The reaction of trialkyl phosphites with aldehydes or ketones in the presence of hydrogen chloride gives dialkyl-1-hydroxy alky Iphosphonates via Arbuzov-type reactions of oxonium salts derived from aldehydes or ketones. This reaction is an alternative to the Abramov reaction.Reduction of activated carbonyl groups, such as a-ketophosphonates by alkyl phosphine, afforded the corresponding reduced products. A new monomer, N-acyl pamidronate (152), which copol5merizes with N-isopropylamide provides a cross linked hydrogel (153) that serves as a substrate for direct biomineralization e.g. the formation of hydroxyapatites). 

Recent developments in metal-catalysed asymmetric addition of phosphorus nucleophiles, with the formation of P-C bonds, have been reviewed the metals and electrophiles have been discussed widely. DFT study of salicylaldehyde-Al(ni)-catalysed hydrophosphonylation of benzaldehyde by diethylphosphonate (DEPH) reveals that P-H activation by the formation of Al-phosphite species is followed by rate-determining C-P bond formation, which determines the predominant (S) configuration (with 99% ee) of the a-hydroxyl phosphonate ester on regeneration of the salicylaldehyde-Al(III) complexes. Reduction of activated carbonyl groups by alkylphosphanes can proceed either through path a or path b (Scheme 35), as evidenced experimentally and theoretically. ... 

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