The 18-crown-6 (18C6) ether adduct of sodium hexachloroiridate [Na(18C6)](2)[IrCl6]center dot xH(2)O (1) was found to catalyze an addition of methanol to a variety of nonfunctionalized alkynes RC=CH (R=H, "Pr, "Bu, "Pen, Ph, HC=C(CH2)(4)) yielding the corresponding Markovnikov addition products (ketals) and in the cases of hex-1-yne and hept-1-yne also anti-Markovnikov ones (acetals, < 10%). Furthermore, the reaction of methanol with octa-1,7-diyne resulted in a double Markovnikov addition to only one triple bond, yielding 7,7-dimethoxyoct-1-yne with 80% degreeof conversion. On the other hand, the regioselectivity in an addition of methanol to functionalized terminal alkynes of the type RC(O)C=CH (R = OMe, Me) was found to be towards anti-Markovnikov products (70-93%). In these two cases vinyl ether intermediates were observed NMR spectroscopically in the course of the reactions. (c) 2007 Elsevier B.V. All rights reserved.