Markovnikov-addition of H-phosphonates to terminal alkynes under metal- and solvent-free conditions

An addition of H-phosphonates to aryl alkynes was realized under solvent- and metal-free conditions, affording Markovnikov-selective α-vinylphosphonates in moderate to good yields. A wide range of aryl alkynes could be applied for the reaction. A tentative mechanism of addition–substitution was proposed based on in situ 31P {1H} NMR studies.