Abstract: Methylpentanediolborane (MPBH) 1 can be prepared easily by reaction of hexyleneglycol with BH3/DMS or B2H6 generated from NaBH4 and I2. MPBH hydroborates stereo- and regioselectively highly functionalized alkynes, including propargyl bromide and propionaldehyde acetal. MPBH compares favorably with pinacolborane in terms of reactivity. The obtained vinylboronic esters are air- and chromatography-stable.