Hydroxy compounds, acylation coupling

Support-bound phenols [173-176] or other compounds with an acidic OH group (oximes [177-179], hydroxamic acids, /V-hydroxy benzotriazoles, etc.) undergo rapid esterification with carbodiimides as coupling agents (Entries 13 and 14, Table 13.12). The resulting products are susceptible to nucleophilic attack, and can be used as insoluble acylating agents. 

The organoindium reagent, prepared from indium metal and bromoacetonitrile, reacts with carbonyl compounds in the presence of chlorotrimethylsilane to give /3-hydroxy nitriles (Scheme 93),336 337 Similarly, indium-mediated coupling of bromoacetonitrile or 2-bromopropionitrile with a variety of aromatic acyl cyanides affords the corresponding aromatic a-cyanoketones in moderate to good yields under mild and neutral conditions (Equation (86)).338 Carbonyl compounds are efficiently transformed into 2,2-dichloro-3-hydroxynitriles by the action of trichloroaceto-nitrile and indium(i) bromide (Scheme 94).339 Bromocyanomethylation of carbonyl compounds is also achieved by the reaction of dibromoacetonitrile and indium(i) bromide.340... 

It might also be noted that, coupled with the facile formation of an [amino(l-hydroxy)alkyl]phosphonic ester, there exists a tested method for the dehydroxylation of such a system this consists in acylation [PhOC(S)Cl, R3N] at OH in the A-protected compound, followed by de-0-acylation brought about with (Mc3Si)3SiH in the presence of aibn. ... 

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