Iron(III)-catalyzed hydration of unactivated internal alkynes in weak acidic medium, under Lewis acid-assisted Brønsted acid catalysis
Alkylarylalkynes are converted with full regioselectivity into the corresponding arylketones by formal hydration of the triple bond under weak acidic conditions, at times and temperatures (<= 95 degrees C) comparable to those used for terminal alkynes. The process catalyzed by Fe-2(SO4)(3)nH(2)O in glacial acetic acid exhibits good functional group compatibility, including that with bulky triple bond substituents, and can be extended to the one-pot transformation of aryltrimethylsilylacetylenes into acetyl derivatives via a desilylation-hydration sequence.