ALKYNE HYDRATION USING PT(II) CATALYSTS

A series of Pt(II) derivatives has been found to be quite effective as alkyne hydration catalysts. These are new and differ from many other hydration catalysts in that there is no need to add protonic acids to or as the media. They are effective for hydration of electron rich alkynes but not useful for electron deficient systems. Finally, using unsymmetrically substituted alkynes, slight regioselectivity is observed with the carbonyl moiety preferring the position closer to the bulky substituent. When substituents have heteroatoms such as oxygen or sulfur, a chelation control process seems to govern the regiochemistry and high selectivities may be obtained.