Carbohydroxylation, cationic

Carbo-oxylation (carbohydroxylation and carboalkoxylation), whereby an organic group and an oxy (hydroxyl or alkoxy) group add across a carbon-carbon double bond or a triple bond, is an important transformation in organic synthesis. We found that the reaction of a cation pool with an alkene or alkyne followed by the trapping of the resulting carbocation by water led to the... 

The reaction of an N-acyliminium ion pool with an alkene or alkyne followed by trapping of the resulting carbocation by water leads to the formation of the corresponding carbohydroxylation product. Cationic sequential one-pot, three-component coupling reactions of an N-acyliminium ion can also be accomplished using an electron-rich olefin and a suitable nucleophile that traps the thus-generated cationic intermediate as shown in Scheme 5.17. ... 

The reactions initiated by the addition of a carbon-carbon multiple bond to the cation pool bring in unique one-pot transformations otherwise difficult to realize, because the reactive carbocations are existing in the solution in relatively high concentration. For example, a sequential one-pot three-component coupling reactions have been developed (Scheme 5) [9, 10]. [4 -f 2] cyclo addition reactions in which an N-acyliminium ion was used as a hetero diene [11], and cationic carbohydroxylation of alkenes and alkynes using the cation pool method [12] were also accomplished. 

Suga S, Kageyama Y, Babu G, Itami K, Yoshida J (2004) Cationic carbohydroxylation of alkenes and alkynes using the cation pool method. Org Lett 6 2709-2711... 

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