Versatile Methodology to Hydrate Alkynes, in the Presence of a Wide Variety of Functional Groups, with Mercury(II) p-Toluensulfonamidate, Under Catalytic, Mild, and Neutral Conditions

Abstract

A method to generate carbonylic compounds from alkynes under mild and neutral conditions, with excellent functional group compatibility and good yields, is described. Hydration takes place under catalytic conditions by using 0.1 to 0.2 equivalents of the easily available and inexpensive mercury(II) p-toluensulfonamidate in a hydroalcoholic solution. After use, the catalyst is rendered inert and/or recycled.

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GRAPHICAL ABSTRACT

Keywords:

• Acetylene
• carbonylic compounds
• catalyst
• hydration
• mercury(II) p-toluensulfonamidate
• regioselectivity
• stereoselectivity

ACKNOWLEDGMENTS

We acknowledge the financial support from the Spanish Ministry of Science and Innovation (Project CTQ-2007-64843). We also thank the University of Barcelona for financial support (UBVRR/2012: AR000126).

Notes

^a Isolated yields.

^b The reaction yields are quantitative by NMR or GC (using internal standard).

^c Conversion in all cases is 100%.

^a Isolated yields (by column chromatography).

^b The reaction yields are quantitative by NMR and GC (using internal standard).

^c The reactions have been performed several times at different scales (20–300 mg), showing robustness. However, a loss of mass has been observed in the case of low-boiling products during workup, especially for those products that form azeotropes with the solvents. Alternative isolation procedures for these products are described in the experimental section.

^d Commercially available substrates.

^e Synthesized substrates.

^a Isolated yields (by column chromatography).

^b Synthesized substrates.

^c Commercially available substrates.