The reaction of an internal alkyne with BH(cy)₂ results in an aldehyde.

Question

Quizplus · Accepted Answer

The reaction of an internal alkyne with a borane derivative, such as BH3 or a disiamylborane like BH(cy)2, typically leads to an anti-Markovnikov addition, resulting in a vinyl borane intermediate. Further processing (oxidation and hydrolysis) would lead to a ketone rather than an aldehyde, as internal alkynes have no terminal hydrogen to form an aldehyde.

The Reaction of an Internal Alkyne with BH(cy)2 Results in an Aldehyde

The Reaction of an Internal Alkyne with BH(cy)₂ Results in an Aldehyde