Chemoselective addition of in situ prepared lithium alkynyl borates to aldehydes: a practical and transition metal free approach toward the synthesis of propargylic alcohols

A convenient synthesis of functionalized propargylic alcohols arising from the 1,2-addition of lithium alkynyl-trimethyl borate onto aldehydes under transition metal free mild conditions is reported. The reaction tolerates a wide range of functional groups, is highly chemoselective and the propargylic alcohols are isolated in good to excellent yields.