Alcohols from alcohol reductive carbonylation

Table 1 Alcohols from the Reduction of Aliphatic Carbonyl Compounds in Protic Solvents.

Alcohols from Reduction of Carbonyl Compounds 609 Problem 17.6 i Predict the products of the following reactions ... 

Selective preparation of unsaturated alcohols from corresponding unsaturated carbonyl compounds is a difficult task to achieve with heterogeneous catalysis. Thermodynamically preferred reduction of double C=C bond can be restricted only with difficulties. Industrial relevance of unsaturated alcohols [1,2] in conjunction with economically expensive methods based on chemical reduction of unsaturated carbonyl compounds calls for the development of new catalysts for highly selective preparation of unsaturated alcohols. 

Reductive carbonylation of nitro compounds is catalyzed by various Pd catalysts. Phenyl isocyanate (93) is produced by the PdCl2-catalyzed reductive carbonylation (deoxygenation) of nitrobenzene with CO, probably via nitrene formation. Extensive studies have been carried out to develop the phosgene-free commercial process for phenyl isocyanate production from nitroben-zene[76]. Effects of various additives such as phenanthroline have been stu-died[77-79]. The co-catalysts of montmorillonite-bipyridylpalladium acetate and Ru3(CO) 2 are used for the reductive carbonylation oLnitroarenes[80,81]. Extensive studies on the reaction in alcohol to form the A -phenylurethane 94 have also been carried out[82-87]. Reaction of nitrobenzene with CO in the presence of aniline affords diphenylurea (95)[88]. 

From the very successful developments of the alcohol dehydrogenase technology for production of secondary alcohols and enzymatic reductive amination of keto-acids for production of amino acids, it is expected that we will also soon see applications for other enzymatic redox chemistries for example, reduction of unsaturated carbonyl compounds with... 

Alcohols from Carbonyl Compounds. Oxidation-Reduction and Organometallic Compounds... 

The grem-dibromocyclopropanes 152 bearing a hydroxyalkyl group, prepared by the addition of dibromocarbene to allylic or homoallylic alcohols, undergo an intramolecular reductive carbonylation to the bicyclic lactones 153. bicyclic lactone derived from prenyl alcohol is an important precursor for the synthesis of ris-chrysanthemic acid. (Scheme 54)... 

Fig. U.4 Reaction sequence showing how a small e.e. of the reagent is converted to a large e.e. of the product by a metal-assisted reaction. In the case shown, a 1 % e.e. of L-valine produced a 51 % e.e. of L-pyrimidine alcohol by the reductive asymmetric transfer of an isopropyl group from zinc to the carbonyl carbon of the...

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