Hydration of terminal alkynes to aldehydes in aqueous micellar solutions by ruthenium(II) catalysis; first anti-Markovnikov addition of water to propargylic alcohols

The hydration of terminal alkynes and of propargylic alcohols to the corresponding aldehyde derivatives is conveniently carried out at 60°C in an aqueous micellar environment, in the presence of 5 mol% of the indenyl ruthenium(II) complex [Ru(η5-C9H7)Cl(PPh3)2]. Higher yields and improved regioselectivity of aldehyde versus ketone as well as reaction conditions, in particular temperature and catalyst load, are found with respect to a solvent mixture 2-propanol–water, due to the aggregating conditions of the micellar solution. The reactions of the propargylic alcohols indicate the tolerance of the hydroxy functionality by the ruthenium complex.