Catalysis from primary alcohols

The selectivity of many reagents and their scope of application have been improved by working in multi-phase systems. Thus dichromate may be used in benzene " or dichloromethane by means of phase-transfer catalysis, and in the latter case aldehydes can easily be obtained from primary alcohols. The reverse type of reaction, namely reduction, can be achieved by cyanoborohydride supported on an anion exchange resin.Other useful functional group interconversions (and removals), RX to RCHO and RX to RH, have been effected with... 

Although quite reliable empirical rules exist for the enantioselectivity of hydrolases for secondary alcohols (see Section 4.2.1.2), such rules are not as developed for primary alcohols, partly because many hydrolases often show low enantioselectivity. With some exceptions, lipases from Pseudomonas sp. and porcine pancreas lipase (PPL) often display sufficient selectivity for practical use. The model described in Figure 4.3 has been developed for Pseudomonas cepacia lipase (reclassified as Burkholderia cepacia), and, provided that no oxygen is attached to the stereogenic center, it works well for this lipase in many cases [41]. However, as soon as primary alcohols are resolved by enzyme catalysis, independent proof of configuration for a previously unknown product is recommended. 

Elimination reactions on alkyl halides follow essentially the same strategy as the halide is usually made from an alcohol. Eliminations of primary groups arc better done this way with base instead of acid catalysis. 

Studies on ligand substitution of metal carbonyls (useful in homogeneous catalysis) (see Suslick et al., 1983b Suslick and Hammerton, 1986) and primary radical formation from n-alcohols (Misik and Riesz, I9%a) suggest that the rate constant decreases linearly with reactant vapor pressure according to Equation 22.12. 

These can be formed from aldehydes and ketones and an aminothiol under acid catalysis with azeotropic water removal [89, 206]. In the pyridoxal series the use of Af-substituted aminothiols has enabled a distinction between two different aldehyde groups the unprotected one could be reduced with sodium borohydride, and the protected group was apparently left unchanged during phosphorylation of the resulting primary alcohol it could then be removed by alkali [207]. 

Enzyme catalysis is specific, controlled, gives few by-products and is generally conducted in water under mild conditions of temperature and pressure. An ideal protocol for the polymer industry. Now, we have pioneers in the laboratory utilizing enzymes to produce addition polymers from vinyl monomers, condensation polymers from alcohols, amines and acids. One addition polymer is in commercial production in the UK utilizing specific enzyme condensation polymerization of primary alcohol groups in the... 

Recently, Dong et al. reported a multicatalytic cascade reaction combining Pd, acid, and Ru catalysis [11]. By coupling palladium-catalyzed oxidation, acid-catalyzed hydrolysis, and ruthenium-catalyzed reduction, the elusive anti-Markovnikov olefin hydration was formally achieved, affording primary alcohols from waters and aryl-substituted terminal alkenes (Scheme 9.8). 

---