A general bifunctional catalyst for the anti-Markovnikov hydration of terminal alkynes to aldehydes gives enzyme-like rate and selectivity enhancements

A new, bifunctional catalyst for anti-Markovnikov hydration of terminal alkynes to aldehydes (6) allows practical room-temperature hydration of alkyl-substituted alkynes. Other outstanding features include near-quantitative aldehyde yields from both alkyl- and aryl-substituted alkynes and wide functional group tolerance. The uncatalyzed rate of alkyne hydration is measured for the first time, showing the enzyme-like rate and selectivity enhancements of aldehyde formation by 6. For aldehyde formation, an uncatalyzed rate <1 x 10-10 mol h-1 means a half-life >600 000 years. The catalyzed rate is up to 23.8 mol (mol 6)-1 h-1 and 10 000:1 ratio in favor of aldehyde. Changes in rate and selectivity induced by 6 are thus >2.4 x 1011 and 300 000, respectively.