Hydroalkoxylation platinum

Hydration and Hydroalkoxylation of Alkynes Gold compounds were first applied to catalyze these types of reactions by Utimoto et al. in 1991, when they studied the use of Au(III) catalysts for the effective activation of alkynes. Previously, these reactions were only catalyzed by palladium or platinum(II) salts or mercury(II) salts under strongly acidic conditions. Utimoto et al. reported the use of Na[AuCI41 in aqueous methanol for the hydration of alkynes to ketones [13]. 

Platinum A less clear-cut case is the observation of the Widenhoefer group of a platinum(II) catalyzed hydroalkoxylation of 4- and 5-aIkenols (Scheme 14a) [19,70], An electrophilic activation mechanism with final protonolysis of a Pt-C bond is discussed, but the substrate range and reactivity of this catalyst system are again close to that expected for an acid catalyst. On the other hand, the authors have performed control experiments to exclude that HCl is a catalyst of the reaction. 

Another very short route to racemic olean comes from Jef De Brabander, and is based on the platinum-catalysed intramolecular hydroalkoxylation of internal alkynes. Under optimised conditions, the 6-exo-dig/7-endo-dig ratio is more than 100 1. [218]... 

Barluenga J, Fernandez A, Di6guez A, Rodriguez F, Fananas FJ (2009) Gold- or platinum-catalyzed cascade processes of alkynol derivatives involving hydroalkoxylation reactions followed by Prins-type cyclizations. Chem-Eur J 15 11660-11667. doi 10.1002/ chem.200900856... 

Qian H, Han X, WidenhoeferRA (2004) Platinum-catalyzed intramolecular hydroalkoxylation of y- and 5-hydroxy olefins to fram cyclic ethers. J Am Chem Soc 126 9536-9537... 

Moreover, in a subsequent paper, a reaction based on a gold- or platinum-catalyzed tandem process that involves an intramolecular hydroalkoxylation of a triple bond followed by a Prins-type cyclization has been reported for the synthesis of [3.3.1]bicyclic compounds starting from easily available alkynol derivatives [152] (Scheme 89). 

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