Acylation of alcohols, by anhydrides

The acylation of alcohols by anhydrides, catalyzed by 4-(dimethylamino)pyridine (DMAP), is one of the most frequently described in the literature examples of nucleophilic catalysis (Figure 5.6). 

In the preceding examples, the asymmetric catalyst is a Lewis acid and hence the catalytic processes reported so far involve electrophilic activation by a metal-centred chiral Lewis acid. There is another strategy, although less explored, which consists of designing chiral Lewis bases for nucleophilic catalysis. It is well known that Lewis bases such as nitrogen heterocycles and tertiary phosphines and amines catalyse a variety of important chemical processes. For instance 4-(dimethylamino)pyridine (DMAP) catalyses the acylation of alcohols by anhydrides the mechanism by which DMAP accelerates this process provides an instmctive illustration of how nucleophiles can... 

Fig. 5.7 Acylation of alcohols by anhydrides. (From http //patentimages.storage.googleapis.com/ US20040127740A1/US20040127740A1-20040701-COOOOZpng).

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